9.Solutions

>n:
Result

l-

of health

drink

Anu has got back home from playfield
after winning a match. She is received

SOLUTIONS

9.1 . SOLUTE

AND SOLVENT

In a solution, the component present in
lesser amount by weight is called soiute
and the component present in a larger
amount by weight is called soivent.
Generally a solvent is a dissolving
medium. It surrounds the particles of
solute

to form

solution.

phases namely, dispersed phase and
dispersion medium. The substance
distributed as particles is
called

dispersed

phase. The continuous

phase in which the colloidal particles
are dispersed is called dispersien
medium.

(Dispersed phase + Dispersion
medium -» Colloidal

solution)

In short, a solution can be represented,
as follows

(Solute + Solvent > Solution)
9.2. TYPES

OF SOLUTIONS

9.2.1. Based on the particle size
Based on the particle
substance,

the solutions

size of the

are divided

into

three types.
1. True seiutiens: It is a homogeneous
mixture

that

contains

small

Fat, vitamin, protein

solute

particles that are dissolved throughout

the solvent eg. Sugar in water.
zeiioidai

selutiarast

It

is

a

heterogeneous mixture made up of two

Q2:
. 1;...9¢

"7.
htéf

in

36
&Ul~.uu§a.I&

Sugar solution

Sivmk
Fig. 9.2 Mixture of sugar and water
forming true solution

Fig. 9.3 A mixture of milk powder and
water forming colloid

0

. St§$§§3§§S§t{.1£§"%S:
It is a heterogeneous
mixture of small insoluble particles in a
solvent. In a suspension, the particles

Students maybe asked to observe t

of solid stay in clusters that are large
enough to be seen (e.g. Chalk powder

the scattering of light (Tyndall effect)
when sunlight passes through the

in water).

window ofthe class rooms.The dust
particles scatter the light making the

pathof the|ightvisib|e.u

>I
I--

SOLUTIONS

Comparing the properties of true solution,colloidal solution and suspension

Particle

size In A0

(1A° =10*°m)

L/V

1A0 to 1OA°

k

1

0A5
t 200°

More than 2000 A0

Visibility
of

Notvisible
evenunder Visibleunderultra B Visible
tothe B

particles

ultra microscope

microscope

naked eye

Diffusionof
particles

diffusesrapidly

diffusesslowly

diffusiondoes not
occur

Scatteringeffect

Does not scatter light

It scatterslight

it does not scatter
light

9.2.2. Based on the type of solvent

1. Unsaturated

Based on the type of solventsolutions
are classifiedintotwo types
1. Aqueous SQ§t.§Q¥§:The solution

2. Saturated

in which water acts as a solvent,
is
called
equecus
sciatica.

For e.g., sugarsolution.
in which any liquidother than water acts
as a solvent is called rtcrz«aqL:eet,:s
carbon

Solution of
disulphide

is

solution

3. Super saturated solution
3.. unsaturated

sciatica:

which the solute

A solution

in

is in lesser amount

in

comparison with the solvent is called

2. Nan-«aqueausactution: The solution

saiutém.

solution

sulphur in
a

suitable

unsaturated

solution. In this, addition

of solute is possible till the solution
reachesthe pointof saturation.
e.g., 5g or 10g or 20g of NaC| in 100g
water

example for non-aqueous solution.

(Benzene,ether,CS2,are someof the
examplesfornonaqueoussolvents.)
9.2.3.

Based

on the amount

on the amount

of solute

asmticn:

which no more
in a definite

of

solute in the given solution
Based

.Sati.:rated

A

solution

in

solute can be dissolved
amount

of solvent

at a

given temperature is called a saturated

solutione.g.,

in the

given amountof solvent,solutionsare
classifiedintothe followingtypes.

i) A saturatedsolutionof CO2in H20

o

ii) 36g of NaCl in 100g of water at room
temperature forms saturated solution

MORE

TO KNOW

3.utaar
saturated
seiutioe:
AsolutionLL7NitrdgenLLinLLLéLa&#
a:eXLaLLmp|é
*Ifozrsatu=ratedfLL
solsutiofn
in?'
nature;

which has more of solute at a given
temperature
solution is

(Earth
soil,;caLn[not
store:si5notregt;csN2

than that of saturated
called super
saturated

tithgmg
itcan;ho|diL).t
i Mi

seiutiora.

>
L:

Testwhethera sLo|ution_Lisi
saturated,i L L
unsaturated
or super-saturated
with V
respect to the addition of salt at a
particulartemperaturetothe solution.

V
L

Take atglass containing 100ml of

l--

water, three packets of salts each 2
weighing 20g, 16g, and 1g and a table L
spoon (see g9.7).

t

L i

LUnsaturated
L

L Saturated L

i

LL~SuLper

SOLUTIONS

9.3. SOLUBELITY

MORE

TO KNOW

Solubility of a solute in a given solvent

Obiiuteiiand
concientratedisoiuiicinsi
concentration
[of fatsolutionfisi
ihe
ifaVmount7;ofOOy
solutesdOissoiOved
;in?V
given amount
iofj.solvent.
O
A solution
V

at a particular temperature is defined as

the number of grams of solute necessary
to saturate 100g of the solvent at that
temperature. For example

SoiubiiiivOi CUS04in H20 is 20-79

at20°C

containingi
less amourit
O
of solute;is
iknown asuiiuie soluution.:OwhTereasOf

a Vsolutmiiconiaining
largeOoiOamoOVuyr 1O
{of-V
isofluteis
knVoWn 'ConceVntrated
solutioin;
It maybVejnotedV
thatdilute
andconcentrated
are theOrelativei

quantiytative
V
Determine
thesolubility
ofa solid(say T
_terms
V and
V th:eyhVaOveonIy
KCI)inwaterjatroomtemperature;-

Preparesaturated
solutionof KCl T-iTakeouttheyevap
orating dish and
in about 30 ml ofjwatert at room V againOweigVhit.eO
OtemOperOature.e
Add

more

of OKCI

Theobservation
andcalculation
are
ensuringthat solutionis saturatedVO
Qivenasf0|Iows.
i i T O
O
~and someKCIisileftundissolved,
9 Filterthe
solutionto
remove
solidjKCl.p
Observation

V V V-

dishi *
Findtemperature
of thesolution
by?Weightofthe

VVVV

i O=Wg

dipping
Oa%theVrm0meteOr
init I '
i Weight
ofdish+saturated

V

- Evaporate
thesolution
todryness
by}solution
ofKCl T S i i i i =W19,
usingalowflametoavoidbumping.TV
weightofdish+ dryKc] i

TV: W29

Allow
thedish
and
solid
tocool
toroom
VCaOIcu|aOt;isoOny
-T _ x V
temperature.
Placethedish
andsolid V V_
e

V SV

_s it - OV

Vinfadessicator
containing
anhydrousWei9h'i0f
Saturated
S0'U'ii0
=(W1;VVV)9

calciuOmOchlorideV
(calcium
chloride
is Weigihtof
KC]

T

=(W2V_VW)g

Vdehydrating
agent,itabsorbs
moisture),
i
. i
V
V i Wéghtof
I
iw eatefpjresent
V
in saturatedsolution V

SATURATED

-

=i<W,W) (W2W)]g
Vi O.
3 [(W1
OW2)gV V

SOLUTION
SATURATED SOLUTION
V OF KCI

V

OF KC|

SAND BATH C &#39;

7Weight of Kcl
_----

; OOi S

x 100

Weight of solvent O

[Solubility
orKcii:
as

<W2vv>

=jxioo

r y(1_W;)i

T

i

6

e.g., Common salt dissolves in water.
A polar compound is less soluble (or)

Tit Bit
100ml

of water

can

insoluble in a non polar solvent.

dissolve 36g of NaC| at
25°C to

attain

saturation.

Solubility of some ionic compounds at 25°c

3. fteet

of grsssure

Effect of pressure is observed only in the

case of gases. An increase in pressure
increases the solubility of a gas in a liquid.

For eg. CO2 gas is filled in soft drinks

>

using the effect of pressure.

a:
I-9.4. FACTORS

AFFECTING

SOLUTlONS

Take 10g of common salt and dissolve
it in 40g of water. Find the concentration

of solution in terms of weight percent.

50g of saturated solution of NaC| at
30°C is evaporated to dryness when
13.2g of dry NaC| was obtained. Find the

solubility of NaC| at 30°C in water.
Mass of water in solution = 5013.2 = 36.8g

Weight percent
h
fh
I
_WeIgtotesoute

X100

Weight
ofsolute
+Weight
ofsolvent

Solubility of NaCl =
M

fN

CI

13.2

-3153--3-x1o =---X100=36g

Mass
= 701%,, x100=20°/o

of water

36.8

Solubility of NaCl = 36g (appx.)

pity evaporatingdish weighs
2g

of

dissolved

potassium
in

12.5

ml

sulphate
of

water.

was
On

cooling, the first crystals appeared
at 60°C. What is the solubility of
potassium sulphate in water at 60°C?

20.0g On the addition of saturated

solutionof NaNO3,the dish weighs66.0g.
When evaporated to dryness, the dish with
crystals weighs 41.5g. Find the solubility

of NaNO3at 20°C.

Weight of saturatedsolutionof NaNO3
12.5 ml of water weighs 12.5g.

= (66.0

20.0) g = 46.0g

In 12.5g of water, amount of potassium Weightof crystalsof NaNO3= (41.5-20.0)g
sulphate dissolved, is 2g

= 21 .5g

In 1g of water, amount of potassium Weight of water in saturated
sulphate dissolved, is 2/12.5 g
= (46.021.5) g = 24.5g
Hence in 100g of water, amount Solubilityof NaNO3=
of

potassium

sulphate

dissolved,

is

(2 x100)/12.5=16g.
The solubility of potassium sulphate in
water at 6090 is 16g.

solution

Weightof NaNO3Crystals
Weight of water

X100

= 31.?
X100
=87.7g
24.5

Solubilityof NaNO3at 20°C is = 87.7g in
100g H20

0

EVALUATION
PART

- A

1. A true solution is a homogeneous
mixture

of solute

and

solvent.

Chalk

powder in water is a heterogenous
mixture.
2.

>-

Solution

is it a true solution?
that

contains

water

9. In an endothermic process, solubility
increases

with

in

temperature. (increase, decrease)
as

the

solvent is called aqueous solution.
If carbon disulphide is a solvent in

PART

a given solution, then the solution is

10. From the table given below, furnish
your points of inferences.

called

I

(saturation, unsaturation)

- B

3. Solubility of common salt in 100g water
is 36g. If 20g of salt is dissolved in it
how much more is required to attain
saturation.

I-

4. If two liquids are mutually soluble, they
are called
liquids. (miscible,

immiscible)

11. Distinguish between the saturated and

Rani shows a piece of chalk to Vani &
asks her to break it into minute particles. The
breaking spree, goes on and on endlessly and
finally they come to conclude that the minute
particle is a group of invisible atoms. They get
set to probe further.
EXPLORING
The
Greek

THE ATOM

word

atom

word

Atomos

indivisible.

John

is derived

Dalton

from

which
modelled

the

means
atoms

as hard indivisible spheres.
His theory remained undisputed for
about a century without any changes.
However

towards

the

end

of 19th

and

in the beginning of 20th centuries, the
introduction of matter wave concept by
de Broglie, the principle of uncertainty
by Heisenberg etc., paved the way for
modern atomic theory or modified
atomic theory.

Fig.101Inner
Weofanat b

10.1. MODERN

ATOIVRC THEORY

The findings of modern atomic theory
are given as follows.
>

Atom

is considered

to be a divisible

>

>

one

element

can

be

The

mass

of

an

atom

can

be

converted into energy. This is in
accordance with Einsteins equation

> Atoms of different elements may be
similar in some respects

E=m&

eg. lsobars(18Ar:0200a40)
> Atom is the smallest particle which
takes part in chemical reactions.

of

changed into atoms of other element
by transmutation.

particle.
> Atoms of the same element may not
be similar in all respects.

eg: Isotopes(WC/35,17Cl37)

Atoms

10.2.

AVOGADRUS

HYPOTHESIS

Amedeo Avogadro
put forward
> The ratio of atoms in a molecule may
be fixed and integral but may not be hypothesis and is based on the relation

simple
e.g.,
CHOHis not a simple ratio
12 22

(Sucrose)

between

number

of molecules

and volume

of gases.
5§.&#39;imgam$
iuawz Equal volumes of
all gases under the same conditions of
temperature and pressure. contain the
equal number of molecules.
10.2.1. Atomicity
The number of atoms present in one
molecule

of

an

element

is called

the

atomicity of an element.
Depending upon the number of atoms
in one molecule of an element, molecules
are classified into monoatomic, diatomic,

triatomic, and poly atomic molecules.

Whena nuclearreactionoccursthe
massof theproductis foundto beless

hanthemassof theyreactants.
The
dierencein mass isconvertedtinto
energyinaccordance
withtheequation

For any homo atomic molecule atomicity
can be deduced using the formula
__

Molecular Mass

Atomicity
=

El=.mc2,
whereE = energyliberated.

m T:disappeared
massandc: speed

of; light. This famousequationof
Einstein.made
revolution
in nuclear
science.
A
AA i A
A
A

Atomic
mass
Avogadros Law enables us to change
over directly from a statementabout volume

ATOMS

MORE

TO KNOW

MORE

AND

MOLECULES

TO KNOW

11
No-of atomspger_

1molecule

lnenuam
(He)
Neon (Ne)
Metals

~Hydrogen
H2M
Chlorine;Cli2_
1

17Ozone
(03)

1. Find the atomicity of chlorine if
its

atomic

molecular

-phosphorous
P4

*Sulphu_r
S31
1 ya"

mass
mass

is 35.5

and

its

is 71

Find the atomicity of ozone if
its

atomic

molecular

mass
mass

is

16

and

its

is 48

e.g.,
N2+ 02 > 2NO
Nitrogen Oxygen
(1 Vol)

(1 Vol)

Nitric oxide
(2 Vols)

After applying Avogadros Law, the
equation,becomes

N2
1 Molecule

+

02 >
1 Molecule

2 NO
2 Molecules

It is found

that

two

molecules

of nitric

oxide contains 2 atoms of nitrogen and
2 atoms of oxygen.

These two atoms of nitrogenand the two
atoms of oxygen should have come from

1 molecule
of nitrogenand1 molecule
of
OX)/99, |&#39;eSPeCtiVe&#39;Y-

Hence, nitrogen and oxygen are called
diatomic

molecules

and

are written

as

N2and 02.

Multiplying both sides by 2, we get

This proves that, atomicity of Nitrogen

Mass of 1 molecule of gas or vapour

is 2 and the atomicity of oxygen is 2

2 XV.D=

Thus Avogadros hypothesis is used in
the deduction of atomicity of elementary

2 x V.D = relative molecular mass of a gas

Mass of 1 atom of hydrogen
or vapour

2xVapour
density
=Relative
molecular

gases.

mass
%. Raietiva

toiacdéar

Mass:

as the ratio of the mass

It is defined
of 1 molecule

of the gas or vapour to the mass of
1 atom of hydrogen.
Relative molecular mass of a gas =
Mass of 1molecule of the gas or vapour

Howto arriveat thevalueof GRAM
MOLARVOLUME
(GMV)
V

GMV=
--DENSLITY
OF
GAS
AT
STP

Mass of 1 atom of hydrogen
ii. Vapour emity
as the

ratio

{Ei}:

of the

It is defined

mass

of a certain

volume of the gas or vapour to the
mass of the same volume of hydrogen
at the same temperature and pressure.

GHAM MOLAR MASS

Tofindthey
valueof
I
GMV

_ to

1

GMMofO2

OF OXYGEN

1

V
= ....___.._

DENSITYOF 02

1=g32/1.429

Mass of 1 volume of gas or vapour

V.D
_

=22.4
lit
Mass
of1volume
ofhydrogen

Therefore
GMV
=22.:4tlitre
atSTP

Applying Avogadros Law,
Mass of 1 molecule of gas or vapour

V&#39;D
_ Mass
of1molecule
ofhydrogen
Since hydrogen is diatomic,
Mass of 1 molecule of gas or vapour

_ 2 XMassof 1 atomof hydrogen

MORE

TO KNOW

ATOMS

AND

MOLECULES

2. It is helpful in determiningthe molecular
formula of gaseous compound.
3. It establishes the relationship between
the vapour density and molecular mass
of a gas.
4. It gives the value of molar volume of
gases at STP. Molar Volume of a gas
at STP=22.4 lit (or) 22400 cm3.
5. It explains Gay Lussacs law effectively.

Name

the

number

AND

atoms

in

find

one

their

molecule

atoms.

It retains

the characteristics

of an

element.

A molecule can exist freely and it is a
form

of bonded

units

whereas

an atom is a singular smallest form of non

MGLECULES

Atoms and molecules are the building
blocks

of

and

) Nitrogen b) Water c) Ammonia
d) Sulphuric acid.

combined

16.3. ATOMS

elements

of the matter.

bonded

unit.

10.3.3.

Differences
and

between

atom

motecule:

10.3.1. Atom: It is the ultimate particle
of an element which may or may not
have

independent

atoms

of

certain

existence.
elements

The

such

as

hydrogen, oxygen, nitrogen, etc.do not
have independent existence whereas

atoms

of

helium,neon,argon,etc.

do

have

independent

All

elements

are

existence.

composed

of

atoms.

10.3.2.

_;Th*e[smalIest, fThesmallestV :
i trparticletlofanr ipartijclelliofan
f;l ~

feleiment
that ielementorfai1 :
that. ~
I can;
stakeDart?
" compound
i r
r inaichlemiicalj canexist{free|y.
lreaction.

isfarl
Anatomisa.A molecule
Molecule:

A molecule

is the

simplest structural unit of an element (or)
a compound which contains one (or) more

jnonbonded; &#39;
btonded
entitytt

lentitv

:_iAn
atom
may A;moleclulecan
.or maynot

_%eXistlfre:ely;p

=existfreelyj}_ i ;

Molecules are of two types, namely
homo

atomic

molecules

and hetero

atomic

molecules.

These

Fig 10.2 Molecule of water

are

the

molecules

which

are

made up of atoms of the same element.

Most of the elementary gases consist of
homo atomic

molecules.

For example

Relative
the ratio

atomic
of mass

mass

of an element

of one

atom

is

of element

hydrogen gas consists of two atoms

to the 1/12" part of mass of one atom of

of hydrogen (H2).Similarly oxygen gas
consists of two atoms of oxygen (02). In

carbon.

accordance

and has no unit.

with

the

number

of atoms

Relative atomic mass is a pure ratio
If the atomic

mass

of an

present in these molecules they are

element is expressed in grams, it is known

classified

as gram atomic mass.

as monoatomic,

diatomic,

triatomic or poly atomic molecules showing
that they contain one, two, three, or more
than three atoms respectively.

The

hetro

atomic

molecules

e.g.,
Gram
atomic
mass
ofhydrogen
=1g

are made

up of atoms of different elements. They

Gram atomic mass of carbon = 12g

are also classified as diatomic, triatomic, or

Gram atomic mass of nitrogen = 14g

polyatomic molecules depending upon the

Gram atomic mass of oxygen = 16g

numberof atomspresent.H20, NH3,CH4,

Gram atomic mass of sodium = 23g

etc., are the examples for hetero atomic
molecules.

10.4.

Atomic mass is expressed

REi..A"i"iVE

Atomic

MASS

(RAM)

RAM=

mass unit (amu). One atomic mass unit
is defined as 1/12" part of the mass of
one

Mass of 1 atom of an element

Mass
of1atom
ofhydrogen

in atomic

atom

10.5.

of carbon.

REi..A&#39;i"iVE
MOLECULAR

iviASS(RiViM)
10.4.1. Definition
hydrogen

(based on
scale)
Massof 1 moleculeof an element/ compound

The relative
is the
element

ratio
to

atomic

of mass
the

mass

of an element

of one

mass

of

atom
one

of the

atom

RMM
=

of

Mass
of1atom
ofhydrogen

hydrogen taken as standard.

18.4.2. Definition (based
on carbon scale)

RAM = 1a

Mass of 1 atom of an element

The

relative

molecular

mass

of

an

element
or a compound is the ratio of
RMM
=
mass

of one

molecule

of the

element

or

thpartofthemassofoneatomofcarbon a compound to the mass of one atom of
hydrogen.

Massof 1 moleculeof an element/ compound

11_2th
part
ofthemass
ofone
atom
ofcarbon

ATOMS

The

relative

molecular

mass

of

AND

MOLECULES

an

element or a compound is the ratio of
mass

of one molecule

of the element

or a

compound to the mass of 1/12 th part of
mass

of one atom

of carbon.

Relative Molecular mass is a pure ratio
and has no unit.

If the molecular

mass

of

a given substance is expressed in gram, it

is known as gram molecular mass of that
substance.
Molecular

mass

is the

sum

of

the

masses of all the atoms present in one
molecule of the compound or an element.
Gram

molecular

mass

calcula-

tions to test your numerical skill

Shown here in Fig.10.3 are one
mole quantities of each of the following
materials: (clockwise from top left) 180g
of acetylsalicylic acid (aspirin), 18.0g of
water, 342g of sucrose (table sugar), 201g

calculation
2(H)
=2x1=2
1(O)=1x16=16
F
ill/lole
Invarious
forms

Gram molecular mass of H20: 18g

of mercury, 55.9g of iron, 58.5g of sodium
chloride (table salt), and 254g of iodine.
10.6.1.

1(C)=1x12=12

2(O)=2x16=32
44

Mole

Definition
is defined

of mole
as

the

amount

of

substance that contains as many specified
elementary particles as the number of
atoms in 12g of carbon-12 isotope.
One mole

is also defined

as the amount

of substance which contains Avogadro

Therefore, one mole of any substance
contains Avogadro number of particles.The
particlesmay be atoms, molecules,ions etc.,
For eg. one mole of oxygen

atoms

FOLLGW

UP:

Find the number

of moles

for remaining problems given above.

represents 6.023 x 1023atoms of oxygen
and 5 moles of oxygen

5x 6.023x1023

atoms contain

atoms

To find the number

b.

of oxygen.
of moles,

the

Calculate
Solution:

the mass
mass

mass x number

= 55.9 x 0.5 = 27.95 g
FOLLQW

elllleass

of moles = -~-~.:----atomic

Number
of moles=

= atomic

of iron

of moles

following formulae are useful
Number

of 0.5 mole

mass

Find the mass

of 2.5 mole

of oxygen atoms
Mass

motecular mass

UP:

= molecular

mass

x number

of

moles

Number
ofmoles
= NQBf3mm:
6.023

6:»:la

No. oflmulecu.le.s

Number of particles =

Number
ofmoles
=

Avogadro number x given mass

gram molecularmass

6.023
as:
£1023
a.

Calculate

the number.

11gof CO2
wA&#39;rcHou&#39;r:
0
Solution: gram

ltmaybenoted
thatwhileusing
the

, termmoleit is essentialto specify;
1thekindof particliesinvolved.
10.6.2. Problems
concep

Number

(based

6O23x1023x11

of molecules

=
44

= 1.51 x 1023 molecules

on mote
FQLLOW

UP:

Calculate

the

number

of

molecules in 360g of glucose.

of moles

=

given mass
atomic

a. Calculate

in

molecular mass of

CO2=44g
Number.

of molecules

the number

of moles

mass
in

i) 81g of aluminium ii) 4.6g sodium
iii) 5.1g of Ammonia iv) 90g of water
v) 2g of NaOH
given mass
81

Number
ofmoles
= atomic
mass= -57
= 3 moles

of aluminium

Mass

of a substance

gram molecularmass x numberof particles
6.023
a. Calculate

the

mass

x 1023
of 18.069

x 1023

moleculesof S02
Sol: Gram molecularmass 802 = 64g

ATOMS

Massof S02

AND

MOLECULES

3.0115x 1023
= T

64X18.069
X1023
=

= 0.5
I
6023
X1023
mo
es

= 192 g
6.023 x 1023

b. Calculate number of moles in 12.046x 1022

atoms of copper

b. Calculate the mass of glucose in

2 X 1024molecules

Numberof molesof atoms

Gram molecular mass of glucose = 180g

Number of atoms

Mass of glucose

Avogadro Number

180 x 2 x 1024

12.046

= 597.7g

=

5-023
X1023

12046 X 1023moleculesin CaO_

x 1022

I
6.023x
1023= 0.2 mo
es

molesin 24.092x 1022moleculesof water.
MORE

TO KNOW

a. Calculate the number moles for a substance

containing3.0115x 1023moleculesin it.
Number

of moles

Number
= T

of molecules

Avogadro
Number
Answers
:
1. 162.4g of 596/3
2. 159.69of CEJSO4
3. 27g of/ll
4. 56g of Fe

5. 58.5 g of Nacl
6. 32g of S
7. 129&#39;
ofC
8. 200. 6g of Hg

Fig. 10.4 More illustrationsfor mole in variousforms

EVALUATIQN
PART

- A

1. From the given examples, form the pair of isotopes and the pair of isobars

1aAr4o17C|35*2oCa40~
17C|37
2. Molecular mass of nitrogen is 28. Its atomic mass is 14. Find the atomicity of
nitrogen.
3. Gram molecular mass of oxygen is 32g. Density of oxygen is 1.429g/cc. Find the
gram molecular volume of oxygen.

4. Clrepresentschlorineatom, CIZrepresentschlorinemolecule.
List out any two differences between atoms and molecules.
5. Calculate the gram molecular mass of water from the values of gram atomic mass
of hydrogen and of oxygen.

Gram atomic mass of hydrogen = 1g
Gram atomic mass of oxygen

= 16g

6. One mole of any substance contains 6.023 x 1023particles.

If 3.0115x 1023particlesare presentin CO2.Find the numberof moles.
PART

- B

1. Modern atomic theory takes up the wave concept, principle of uncertainty and
other latest discoveries to give a clear cut picture about an atom. State the
findings of modern atomic theory.
2. You are given the values of mass of one volume of oxygen gas and the mass of

one volume of hydrogen. By applying Avagadros law how will you establish the
relation between vapour density and molecular mass of a gas?
3.

Calculate

the number

of moles

in

a. 12.046 x 1023atoms of copper
b. 27.95g of iron

c. 1.51x 1023moleculesof CO2

FURTHER
REFERENCE:
VB;oioi<fs:4.
3
Cllemtistryl:
a%5,nVd2.is;har:"rtVaL
-gvishtall
1.PUb&#39;icati*ons,1
.
*

1

y

VLFifi= inorganicChemistrysi4:2?.L,.S0r§iV
.W3ebfsitei3
:3www.eh.ow..Com/atorhsandmolecu
M4
if 3"3V
F

3www.che3m4kids.corn/tag/atomsandmo

>-

CHEMICAL

REACTIONS

You observe a deep yellow precipitate,
Do yo u obs e rve an y b ris k
dont you?
effervescence? It is due to the evolution
of carbon dioxide gas.

Fig. 11.2 Yellow precipitate of lead iodide.
_
_ _

Fig. 11.3 Reaction of calcium

&#39;1
I8 lead |0d|d9(l0b|2)-

carbonate
withdil.HCl

These

. ,1Take5gi.ioi1
calciumoxide(quick .

are

some

of

the

common

observations in a chemical reaction. From

jglimfe)in1agbeaker;:
V7V. C325V1e

g it theactivities
thatwehavediscussed,
it
l
waterto
itts|owg|yt:ggf:.
fi1]g:i...isclearthatchemical
reactions
willbring
Touch
thebeiaker7i*j t}[}:{f abouta permanent
change
resulting
in
feel?
V i M 1L theformation
ofnewproduct(s).
111 1111 111

The substances taking part in the

Do you feel hot?
happens
Calcium

oxide

Let us see what

reaction
those

reaction

is

formed

known

as

as a result

reactants

and

of the reaction

are called products.

reacts

with

water

to

produceslakedlime(calciumhydroxide).
This

are

exothermic

and

MQRE To KNQW

will

be accompanied by hissing sound
and bubbles leading to the release of
considerable

amount

of heat.

Takea
pinch
ofcalcium
cargonateii
I powdertiniatestgitube. V

. Adddilutehydroiohmric
acid 1
1Notethechaniges
iinjfthetest
tube.
carefully

11-

E

>-

CHEMlCAL

REACTIONS

(NH4)2cr2o,é»
C1203?
.1.N21+ 411201
MORE

TO KNOW

Fig. 11.5 Heating the test tube
containing copper carbonate

Change of colour from green to black is
observed. This isduetothe decomposition
of copper carbonate to copper (ll) oxide.

CuC03A+
CuO+ CD21
In the reaction between A and BC, A

displaces B from BC to form AC. This
Take lead nitrate In a test tube
Heat

it over

1

shows that A is more reactive than B.

the flame

Observe the changes

Take20 ml of coppersulphate
solution

Liberationof a reddish brown gas (N02)
is

observed.

This

is

because

of

the

decomposition of lead nitrate into lead
oxide, nitrogen dioxide and oxygen.

2%(§\:o3;2was ~§~
4l\t02§
+ pg?

in a beaker

Dropan
ironnailintothebeaker
Leave it for few days

Observe
thecolour
ofthecopper
sulphate solution and the iron nail

From the above two activities (11.6
and 11.7), It can be noted that a single
compound breaks down to produce
two or more substances. Such type
of reaction is called decomposition

1-

reaction.

1-

Someotherexamplesfordecomposition
reaction:

11::

ga

Cacoa_A,Cao + COZT

Fig. 11.6Irondisplacescopperfromcopper

sulphate
solution

E

Blue colour of the copper sulphate
solution changes into green colour and the
iron nail acquires a brownish look. It is a
noticeable change. is it not? This change
confirms

that

iron

is more

reactive

than

solutionin a testtube

1

Inanother
testtube,
take5mlof

barium chloride

if

copper. The following chemical reaction
takes place in this activity.

AMixboththesolutions

Fe + CuS04->FeSO4+Cu

What do you observe?

>-

In this reaction, iron displaces copper

from CuSO4solution.

I

Take5.: of sod m sulphate.

Repeat Activity
rod

instead

11.8 but use zinc

of an iron

nail.

What

colour

changes do you observe on the rod and in
the solution? Write the chemical equation.

IOther example:

* 1 1CHEMICAL

REACTIONS

Double decomposition reaction is Oxidation:
A chemical
reaction
which involves
any reaction in which exchange of ions
between two reactants occur, leading to addition of oxygen or removal of
the formation of two different products. hydrogen or loss of electron(s) is
called

Other example :

as oxidation.

2Mg «-102 .+ ZMQO(addition
ofoxygen)

cuso, + H2S-»>
Cusl + H2304

HZS+ Br2~>2HBr + S (removal
ofhydrogen)
Fe + Fe3*+ e (lossof electron)

We

are

all aware

of the fact that

oxygen is the most essential element
for sustaininglife. One can live without
food or even water for a numberof days,
but not without oxygen. In our daily life
we come across phenomena like fading
of the coloursof the clothes, burningof
combustiblesubstanceslike cookinggas,
wood and coal, and also rustingof iron
articles. All such processes fall in the
category of a specific type of chemical
reaction

called

oxidation

reduction

reaction(redox reaction). A large number
of industrialprocesseslike electroplating,
extraction of metals like aluminium, are

Reduction:
A chemical

reaction

which

involves

addition of hydrogen or removal of
oxygen or gain of electron(s) is called
as reduction.

2Na 4-H2«-+2Nal-I(additionof hydrogen)
l

(removalof oxygen)

Fe3*+ e -> Fe2*(gain of electron)
Redo):
A

reaction:
chemical

reaction

in

which

oxidation and reduction take place
simultaneously is called redox reaction.

Zn ~i~
333%,,-s«Cu ~i~
Eng
Attemptto write any other redox reaction

based uponthe redox reaction.

1-

aoper
(lloxide
Oxidation

Fig. 11.8 Redox reaction

1-

E

>I

I-

During the conversion of copper(||)
oxide to copper, the copper(||) oxide is
losing oxygen and is being reduced. The
hydrogen is gaining oxygen and is being

dissolved in water to wash clothes, heat

redox

a. Emtftarmic

is given out. When glucose is kept on
our tongue, a chilling effect is felt. During
these processes, heat is either given out
oxidised. In other words, one reactant or absorbed from the surroundings. In
gets oxidised while the other gets reduced the same way, in most of the chemical
during the reaction. Such reactions are reactions, energy is either taken up or
called oxidation
reduction
reactions
or
given out.
reactions.

Oxidation

is

Gain of oxygen
Loss of hydrogen
Loss of e|ectron(s)

Reduction

is

Loss of oxygen
Gain of hydrogen
Gain of e|ectron(s)

The

raactitzms

chemical

reactions

which

proceed
with
the evolution
of
heat energy are called exothermic
reactions.

CHEMICAL

+ ve sign indicates increase in concentration

11.2.1

of B with

zinc

reacts

with

both

1M

hydrochloric acid and 2M hydrochloric
acid, the rate of evolution of hydrogen
gas is more from the test tube B than

time.

FACTORS

Granulated

REACTIONS

INFLUENCING

THE RATE OF THE CHEMICAL

from the test tube A. This is because, 2M

REACTION

hydrochloric acid is more concentrated
than 1M hydrochloric acid. That is, greater
the

concentration

of

the

reactant,

greater will be the rate of the reaction.

I ..Take
mIagne:§.ium.grIibbon,I
intwoytest
I *tubesIAandBI

I

goAdd
hydrochloric
acid
totest
iube7A
; A* Takepowderedcalcium
carbonate
o/Add
,aceticacid
totesttubeBI I

;

I inbeakerA
,

f-I-Observe
thechanges
in twotest .
tubes
&#39;

. 7 Takemarble
[chips
(calcium
I carbonate)in beakerB II

Add hydrochloric
Vacidin both
Magnesium ribbon reacts with both
hydrochloric acid and acetic acid but
reaction is faster in hydrochloric acid
than in acetic acid. Do you know why?
Hydrochloric acid is more reactive
than
of

acetic

acid.

the

reactant

of the

reaction.

It shows

that

influences

nature
the

beakersAandB - gr 7 g

I I .ObserveIthjechangesI,
I
Pwdre ali

crbat

ract mre

quickly with hydrochloric acid than marble
chips. What is the reason?.

rate

Powdered

calcium

carbonate

offers

large surface area for the reaction to
occur

at a faster

rate.

This

shows

that

greater the surface area, greater is the
rate

&#39;
I Take
3gIofigranulted
zic,in~the
7
V,.etesttubeAandB. V I _

L, I

i I Add5 mloii Mhydrochloric
acid
E in testtubeA

L L _ . VL

3 j71Add=
5ml.of2M hydrochloric
acid

ulrintesttubeBT

, by I

I I I 7Observe
thechanges

A

of the

reaction.

(Take
3gofmarble
chips
inabeaker

Add5ymlof,1gM
hydrochloric
acid_

Observe
thechanyges
II

1-

HeatIthebeakerI
V

1-

, Cibservethe
changes
A

L

Calcium carbonate present in marble
chips react slowly with hydrochloric
acid at room temperature and evolves
carbon dioxide at slower rate, whereas on

heating, the evolution of carbon dioxide is
made

faster.This

shows

that

increase

in

temperature increases the rate of the
reaction.

>
L:

Take potassiumchlorate in a test
tube

Heatthe testtube

l--

L

Observe
whathappens
Add manganese
dioxideas a
catalyst

A

MORE

TO KNOW

CHEMICAL

uelitmuspaper

REACTlONS

Source

Acid present

Apple

Malic acid

Lemon

Citric acid

Grape

Tartaric acid

Tomato

Oxalic

Vinegar (food
preservative)

Acetic acid

Curd

Lactic

acid

acid

Fig. 11.9 Acid solution turns blue
litmus paper red

colourless with phenolphthalein and pink
with methyl orange. Many organic acids
are naturally present in food items.
11.3.1

CLASSHFECATSON

OF

ACIDS

are classified into two types namely
organic acids and inorganic acids.
Qrganic actds:- Acids present in
plants and animals (living beings)
are organic acids eg. HCOOH,

CH3COOH
(Weakacids).
inorganic ac§ds:~ Acids from rocks
and minerals are inorganic acids or

mineral acids eg. HCI, HNO3,HZSO4

Whatis the acid present in it?
two hydrogen ions per molecule of the

acid in solutioneg. H2804,H2CO3_
.
It is an acid which gives
three hydrogen ions per molecule of

the acid in solution.eg. H3PO4
MORE

TO KNOW

(Strong acids).

131 A It is an acid which

gives one hydrogen ion per molecule

of the acid in solutioneg. HCI, HNO3_
It is an acid which gives

1-

E

Acids are classified into two types

Take 5 g of zinc granules in a

based

test

on ionisation.

Strong acidsre These are acids which
ionise completely in water eg.HCl
Weak

acidshese

are

acids

tube

Add10mlof dilutehydrochloric
acid through thistle funnel

Duringthe course.of addition,

what do you observe?

which ionise partially in water eg.

CH3COOH
,.
Depending
on the percentage or amount of acid
dissolved

in water

into concentrated

Conssntrated

acids

are classified

acid and dilute

acid.

ac%d:~ It is an

acid

having a relatively high percentage
of acid in its aqueous solution.

Fig. 11.10 Reactionof Zn granules with dilute HCI

Biitjts at:id:~ It is an acid having a

relativelylOWpercentageOfacid in andhydrogengas_

aqueous
solution.

Zn,,_
ZHCI
W,znciz+H2?

MORE TO KNOW

Whena burningcandleis broughtnear
the bubble containing hydrogen gas, the
flame goes off with a poping sound. This
confirms that metal displaces hydrogen
from the dilute acid. (Hydrogen gas burns
with a poping s und)
Metal + Acid + Salt + Hydrogen
Another example

Mg -2-H2SO4+NlgS04 + H2?
MORE

11.3.2
CHEMICAL
PROPERTEES
OF
AClDS

>
cc
l--

Note

that

zinc

reacts

with

dilute

hydrochloric acid to form zinc chloride

6?

TO KNOW

CHEMICAL

REACTIONS

From the above activity the reaction
can be summarized

as

Metal
carbonate
or

+ Acid

salt
->

Water

Take
twotesttubes,
labelthemas Metalbi°arb°"ate

Carbon

IVand II

dioxide

0 Take smallamountofwashing soda

(Na2CO3)
in testtube I andsmall ?xi§gCE$3=%~
2 H93~~~~>
SVEQCEQ
4»Hz + Cgég
amountof baking soda (NaHCO3)
Mg(HCO3)2+
2 HCI-+ MgC|2+ 2H20+ 2CO2T
in test tube ll 1
_
-1 Add dilute hydrochloricacid to both
E?

the test tubes

MORE

o Whatdoyouobserve?- -

1

TO KNOW

hm:

oi Passthe gasproducedin eachcase,
throughlimewater[Ca(OH)2]
solution
and record your obsenlations

.. o.

.. Oxide

in a watch glass and add dilute
hydrochloric acid slowly

Note the colour of the salt

What
hashappened
tothecopper
(ll) oxide?

1

C Fig.11.11
Testing
Coficaribondioxide
CC
Test tube

l

Test tube

ll

1When carbon dioxide is passed
through lime water, it turns milky.

Ca(0H)2+ cog-» CaC03+ H20

(milky)

1-

Fig. 11.12 Reaction of copper(II) oxide with

dilute
hydrochloric
acid

E

The colour changes from black to green.

11_4_ BASES

This is due to the formationof copper Base is a substancewhich releases

Ch|0ride
inthereaCtiOn.
SinCe
metalhydroxide
ionswhendissolved
inWater-

Oxidesare baSi°~theYreactwith acid t0 It is a substancewhich is bitter in taste

form33 andWater-

andsoapyto touch(e.g.Washingsoda,

Cuo + 2HCl -m>
CuCl2+ H20
caustic soda and caustic potash). They
Fromthe above activitywe concludethat change red litmus to blue. They are pink
with phenolphthalein
Metallic
oxide+Acid+Salt+Water methyl
Orange

>
a:
l--

Another example

C33 ~i~
EHCE»~»~
Cam: ~§~
R20

Anacid
produces
hydrogen
ions
inwater.
Hydrogen ions cannot exist alone,
but they exist in the form of hydronium

(H3O+)ions. When water is absent, the
separation of hydrogen ions from an acid
does

not occur.

and yellow with

CHEMICAL

one hydroxide ion per molecule
eg.NaOH, KOH.
miasédés base»

It is a base

11.4.2. Chemical
Bases

REACTIONS

Properties

which

ionises in water to give two
hydroxide ions per molecule eg.

Zinc reacts with sodium hydroxide

Ca(OH)2=
M9(OH)2-

to formsodiumzincatewith the

iriasidis

liberation of hydrogengas.

bases» It is a base which

ionises in water to give three

Zn + 2 NaOHM»Na2ZnO2+
H27

hydroxide

Metal + Base > Salt + Hydrogen

ions per molecule eg.

Al(OH)3,Fe(OH)3.
MORE

Another example

TO KNOW

MORE

Depending
or

amount

water,

on
of

bases

the
base

are

Of

TO KNOW

percentage
dissolved

in

classified

as

concentrated

alkali and dilute alkali.

Consentrateoi

ai§<aii:«~It is an alkali

having a relatively high percentage

Sodium hydroxide reacts with carbon
dioxide gives sodium carbonate and water.

of alkali in its aqueoussolution.

2NaGH+ CO2W»Na2QO3+
H20

mateaikaiitw
Itisanalkalihaving
a Theab°"e"ea°°°°"5 that
relatively low percentage of alkali in Non metallic oxide + Base»~>
Salt-+-Water

Bases generate hydroxide (OH&#39;)
ions
when

dissolved

1-

in water.

NaOH + Na + OH-

1-

E

>-

: CHENHCAL

Same activity can be repeated for dilute

REACNONS

eiuiim

hydrochloric
acid,dilutesulphuric
acid, p
sodium hydroxide solution and potassium

hydroxide
solutionwiththe helpof your
teacher.
s ~ ::

T

I

:1 COLOUR?

=(3)

COLOUR

&#39;"°&#39;°T°"*
INACIDimse
g Litmus: . - Tf

j

P = &#39;09",
(0-001)
p
&#39;
log) 10 [log 10: 1]

p=3

T

is,pheintoiphtha1e;n.

T 2. The hydrogenion concentrationof a

. Methyltorangee.
;g_

solution
is 1.0x 10&#39;9
M.Whatisthep

e Te Te Te Te Te Te Te Te Te Te T

. . , e of the solution? Predict whether the given

its pHSCALE

solution
isacidic,
basic
orneutral.

p stands
forthepowerof hydrogen
Sgmg
ion concentration in a solution. pHvalues
decide

whether

a solution

is

acidic

or

basic or neutral. pHscale was introduced

P

p=|og10(1.0x10&#3
by S.P.L. Sorenson. It is mathematically

pH=(|og101.O
+ iog,01o&#39;9
) [|og,01= 0]
p=(09)=9

Forneutral
solution
[+]=1O"7M;
p =7

pH=9 iep...
>7

FOV
acidic30&#39;U0
[+l > 10"7M; P < 7

Thereforethe givensolutionis basic.

For basic solution [+] < 10"7M; p > 7

3. The hydroxyl ion concentration of a
solution is 0.001M. What is the p of the

When 0 ions are taken into account
the p expressionis replacedby p°*"
,

a

e

312 11V1 0 9

14 S

pol-I f

solution?

1

Q6 5 4J

7

1

2

Settsttm

10

:

pa

pOH=_|Og10(10
3)

pOH=3

pH=14_poH

p=143=11

01 2

45

8 911112131

Thehydroxyl
iOnCOnCentratiOn
Ofa

(--Acidic
nature
increasesi
Basic
nature
increases>
30lUti0nis 1-0X 10-9M-Whatis the PHOf
"em"
1. The hydrogen ion concentration of a

solutionis 0.001M.Whatis the p of the
solution?

the solution?
iv

PO - "°91o[OH1
poi-I
= 40910(1_oX10&#39;9)

11-

E

pOH=9
pH=14_pOH
p=149=5

11.6.1p

>a:
I--

paper

A more common method of measuring
p in a school laboratory is by using p
paper. p paper contains a mixture of
indicators, which gives different colours
across the entire p range. p value of the
various solutions are given in the table.

CHEMICAL

REACTIONS

11.6.2 importance of pt in
p of rain water is approximately
7 showing high level of its purity and

everyday life

(i)

neutrality.If rain water is polluted by S02

Using pl" factor the healthiness of and N02, acid rain occurs,bringingthe p
our body is predicted. At pH level
value less than 7.
6.9, the body becomes prone to
viral infections like colds, cough 11.7 SALT
and

flu.

Cancer

cells

thrive

inside

the body at a p of 5.5.
(ii)

When you say salt, you may think of
white stuff put on chips. But that is just one
salt called common salt. There are many

The p of a normal, healthy human
skin is 4.5 to 6. Proper skin p is other salts used in other fields. Salts are
essential for a healthy complexion. the products of the reaction between acids
and bases (see reaction of acids and
(iii) p of stomach fluid is approximately
bases), which produce positive ions and
2.0. This fluid is essential
for the
negative ions when dissolved in water.
digestion of food.
(iv) Human blood pH range is 7.35 to
7.45. Any increase or decrease in
this value, leads to diseases. The

ideal pH for blood is 7.4.
(v) p of normal saliva ranges between

11.7.1

Ciassificaticn

of salts

A normal salt is obtained by complete
neutralization of an acid by a base

N30}-i + HCl -+ NaCl + H20

6.5 to 7.5.

(vi) White enamel coating in our teeth
Acid salts are derived by the partial
is calcium phosphate, hardest
replacement of hydrogen ions of an acid
substance in our body. It does
by a metal. When a calculated amount of
not dissolve in water. If p of
a base is added to a polybasic acid, acid
mouth falls below 5.5, the enamel

gets corroded. Toothpastes are
generally basic, and is used for
cleaning the teeth, can neutralize
the excess acid and prevent tooth
decay.

salt is obtained, as follows.

ages 4%
ages,

N§H$§4~i*was

Basic salts are formed by the partial
replacement of hydroxide ions of a diacidic
or triacidic base by an acid radical.

1-

important. Citrus fruits require slightly

A basic salt may further reacts with an
acid to give a normal salt.

alkaline soil, while rice requires acidic soil

eageezgg
»~§~
tr-ESE:ebgetagct.4»
ago

and sugar cane requires neutral soil.

(Diacidic base)

I

In agriculture, the p of soil is very

Basic salt

1-

used

Double salts are formed

by the

to make

cake

and bread

soft

and spongy .

2. It is an ingredient in antacid. Being
simple salts in equimolar ratio followed by
alkaline, it neutralises excess of
crystallization.
acid in the stomach.
e.g. potash alum
combination

of

$137.2 USES

>-

saturated

solution

of two

OF SALTS

water

It is used in our daily food and as
preservative.

E
I-

1. It is usedfordisinfecting
drinking

1. It is used in softening hard water.
2. It is used as a cleaning agent for
domestic purposes.

to

make

it

free

from

microorganisms.
2. It is used for bleaching cotton and
linen in the textile industry
It is used for plastering fractured bones
and in making casts for statues

GRCDJUVPDACTIVITY
Prepare the 2following salt in the

&#39;
CHEMICAL

REACTIONS

6. When aqueous solution of silver nitrate
and sodium

chloride

are mixed

precipitate is immediately
(white / yellow / red).

formed

7. aluminium can displace Zinc metal
from aqueous solution of Zinc sulphate
(zinc is more reactive than aluminium /
aluminium is more reactive than zinc).
. To protect tooth decay, we are advised
to brush our teeth regularly. The nature
of the tooth paste commonly used is
in nature.

9. Vinegar is present in acetic acid. Curd
contains
acid (Lactic acid /
Tartaric acid).

10.p =

logm[Ht].The p of a solution

containing hydrogen ion concentration
of 0.001M solution is
(3 / 11 / 14)
PART

- B

Baking soda
°Se°&#39;
ammonia

analyse the data in the table and
answer the following questions
a. Which

12.The p values of certain familiar
substances are given below

is acidic

b. Which substances

in nature?

are basic in nature?

13.Why does the colourof coppersulphate
change when an iron nail is kept in it?
Justify your answer.
14.The hydroxyl ion concentration of a

solutionis 1.0x 10"3M.Whatis the p"
of the solution?

_
_
15. Equal lengths of magnesium ribbons
are

11.What type of chemical reaction takes
place when i) limestone is heated ii) a
magnesium ribbon is burnt in air

substance

taken

in

test

tubes

A

and

B.

Hydrochloric acid is added to test
tube A, while acetic acid is added to
test tube

B. Amount

taken

for both

which

test

tube

the

and concentration
acids

reaction

are same
occurs

in

more

vigourously and why?

EFEURTHERREFERENCE
yBooks:g L is.

C E A 1.

.ggpp.p .

.

. 1.

V .

1.Text
bookofinorganic
ChemistryP.L.
Soni~S.Chand
8:sonspublishers

. A 2.Principlesof
PhysicalChemistryiBt.R.
Puri,CL.Ri.tSharmaVishalpublishe
A . E 1 *

.Websitie7:f .

A A www.ask.ComE E

www.chem4kids.com

11-

E

PEFHODIC

CLASSlF!CATlON

12. Periodic classification
Have you ever visited a library? There
are thousands of books in a large library.
If you ask for a book in general it is very
difficult to trace. Whereas if you ask for a
particular book, the library staff can locate
it very easily. How is it possible? In library
the

books

are

classified

into

various

categories and sub categories. They
are arranged on shelves accordingly.
Therefore locating books become very
easy.

As on date one hundred and eighteen
elements are known. It is difficultto identify
each and every element individually and
to know its property and uses. Therefore
they have been classified on the basis
of their similarities in properties. One of

OF ELEMENTS

M BIEIIIBIIIS

12.1. MODERN

PERIODIC

LAW

A large number of scientists made
attempts to eliminate the drawbacks of
Mende|eevs periodic table. In 1912,
Moseley,an Englishphysicistmeasuredthe
frequencies of X-rays emitted by a metal,
when the metal was bombarded with high
speed electrons. He plotted square roots of
the frequencies against atomic numbers.
The plot obtained was a straight line. He
found that the square root of the frequency
of the prominent X-rays emitted by a metal
was proportionalto the atomic number and
not to the atomic weight of the atom of that
metal.

MORE

TO KNOW

t Henry GwynJeffreys Moseley,
an English physicist
(1887-1915), used
X-rays to determine
the atomic numbers
. of the elements.

Moseley suggested that atomic
number (2) should be the basis of the
classification

the important instincts of mankind is to be
systematic. Scientists felt the necessity to
group elements of similar characteristics
together so that if the properties of one of
them are known, those of the others could

be guessed and related.

of the element. Thus, he

gave modern periodic law as follows:
Modern periodic law states that the
physical and chemical properties of
elements are the periodic function of
their

atomic

numbers.

Thus, according to the modern
When a large number of elements were
periodic law, if elements are arranged
discovered, several attempts were being
in the increasing order of their atomic
made to arrange them on the basis of their
numbers,
the elements with similar
properties, nature, character, valency,
properties are repeated after certain
etc., (Real credit for preparing the periodic
regular intervals.
table goes to Mendeleev).

12.2. MODERN

PEFHCDIC

TABLE

12.2.3. Study of periods

The
horizontal
rows
are
called
Based on the modern periodic law, a
number of forms of periodic table have
MORE
been proposed from time to time but
general plan of the table remained the
same as proposed by Mendeleev. The
table which is most commonly used
and which is based upon the electronic
configuration of elements is called the
periods. There are seven horizontal rows
long form of the periodic table. This is
in the periodic table.
called the modern periodic table.

a First period (Atomic number 1 and 2):
This is the shortest period. It contains
only two elements (Hydrogen and
Helium).

12.2.1. Description of modern or
long form of the periodic
table

Long form of the periodic table is a chart
of elements

in which

the

elements

have

been arranged in the increasing order of
their

atomic

numbers.

This table

consists

of horizontal rows called periods and
vertical

columns

called groups.

o Secend period (Atomicnumber3 to 10):
This is a short period. It contains eight
elements (Lithium to Neon).
Third period (Atomic number 11to 18):
This is also a short period. It contains eight
elements (Sodium to Argon).

12.2.2. Different portions of long form of periodic table

;»L0ng
fotmof «
periodic table

*:;-PERIODIC

w ?¬}§.§ti§"%
psrisd (Atomicnumber19to 36):
This is a long period. It contains
eighteen elements (Potassium to
Krypton). This includes 8 normal
elements

and

10 transition

elements.

at Fifth parted (Atomic number 37 to 54):
This is also a long period. It contains
18 elements (Rubidium to Xenon).
This

includes

10 transition

8 normal

elements

and

CLASSIFICATION

o Group 15 is Nitrogen family.
o Group 16 elements are called
chalcogen family (except polonium).
o Group 17 elements are called halogen
family.
o Group 18 elements are called noble
gases or inert gases.
o

The

Lanthanides

inner

This

includes

10 transition

8 normal
elements

and

elements,
14 inner

transition elements (Lanthanides).
s $evsr*stt&#39;t
psrtsd (Atomicnumber87to 118):
As like the sixth period, this period
also

can

accomodate

32

elements.

Till now only 26 elements have been
authenticated by IUPAC

and actinides

which

form part of the group 3 are called

elements.

an Sixth perfect (Atomic number 55 to 86):
This isthe longest period. ltcontains
32 elements (Ceasium to Radon).

OF ELEMENTS

transition

elements.

12.3. CHARACTERBTSCS
MODERN
12.3.1.

GF

PEREODKI TABLE

Characteristics

Of Periods

o In a period, the electrons are filled
in the same
elements.

valence

shell

of all

c As the electronic configuration
changes along the period, the
chemical properties of the elements
also change.

12.2.4. Study of groups

o Vertical columns in the periodic table
starting from top to bottom are called
groups. There are 18 groups in the
periodic table.

-

earth

metals.

elements

.

o Group 1, 2 and 13 -18 are called normal
elements or main group elements or
representative elements .
o Group 13 is Boron family.
o Group 14 is Carbon family.

elements

in a

o In a period, the metallic character of
the element
nonmetallic

decreases
character

while

their

increases.

of Groups

o The elements present in 2 and 18
groups differ in atomic number by

o Groups three to twelve are called
transition

of the

12.3.2. Characteristics

o Second group elements are called
alkaline

size

period decrease from left to the right.

o First group elements are called alkali
metals.

Atomic

8,8,18,18,32.

-

The elements present in 13
17
groups differ in atomic number by
8,18,18,32.

o The elements present in 4 - 12
groups differ in atomic number by
18,32,32.

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62.

PERIODIC

o The elements present in a group
have the same number of electrons
in the valence shell of their atoms.

-

The elements present in a group
have the same valency.

o The elements present in a group
have identical chemical properties.
o The physical properties of the
elements in group such as melting
point, boiling point, density vary
gradually.
o Atomic radii of the elements present
in a group increases downwards.
12.3.3. Advantages
Periodic
-

The

table

of the Modern

Table
is

fundamental

based

on

property

a

more

ie., atomic

number.

o it
the

correlates
element

the
with

position
its

of

electronic

configuration more clearly.
a The completion of each period is
more logical. In a period as the
atomic number increases, the
energy shells are gradually filled
up until an inert gas configuration
is reached.

o

it is easy
reproduce.

CLASSIFICATION

The position of eighth group
(in Mendeleevs table) is also
justified in this table. All transition
elements
have been brought
in the middle as the properties
of

transition

to

remember

and

has been discarded.

are

intermediate between left portion
and right portion elements of the
periodic table.
The

table

metals

completely

from

separates

non-metals.

The

non-

metals are present in upper right
corners of the periodic table.
The positions of certain elements
which were earlier misfit (interchanged)
in the Mendeleevs
periodic table are now justified
because
number

it is based
on
of the elements.

Justification

has

been

atomic

offered

for

placing lanthanides and actinides
at the bottom of the periodic
table.
32.3.4.

Defects

in the Modern

Periodic

Table

Position of hydrogen is not fixed

Position

of

lanthanides

and

actinides has not been given inside
the main body of periodic table.
It

does

distribution

One position for all isotopes of
an element is justified, since the
isotopes have the same atomic
number.

elements

till now.

o Each group is an independent
group and the idea of subgroups
-

OF ELEMENTS

of

transition

elements.

not
of

reflect
electrons
and

inner

the
of

exact
some

transition

MORE

12.4.

TO KNOW

IVIFTALLURGY

I (Al ) am a light silvery
white metal to build aircraft.

So, I am great.

I ( Fe ) am a lustrous steel
metal to make machineries

and bridges.So, I am great.

I ( Cu ) am a reddish brown
metal to make coins.

So, I am great.

Individuallyyou
are great in your
aspect.You will
become the
GREATEST IF
YOU ARE
ALLOYED
TOGETHER.

Unity is strength.

PERIODIC

CLASSIFICATION

OF ELEMENTS

INTRODUCTION

Metallurgy is as old as our civilization.
Copper was the first metal to be used for

making utensils, weapons and for other
works. Metals play a significant role in our
life. They constitute the mineral wealth of a
country which is the measure of prosperity.
Metals

like

titanium,

chromium,

manganese, zirconium etc. find their
applications in the manufacture of defence
equipments. These are called strategic
metals. The metal uranium plays, a
vital role in nuclear reactions releasing
enormous energy called nuclear energy.
Copper, silver and gold are called coinage
metals as they are used in making coins,
jewellery etc.
MORE

Viefnameses
CraftWorkinsilver

TO KNOW

Aluminium

foil

Bangles
MORE

TO KN

W

12.4.1.

TERMINOLOGIES
METALLURGY

IN

a large scale is said to be a ore.

Minerals: A mineral may be a single
For example, clay (A|2O3.2SiO2.2H2O)
compound or complex mixture of various
and bauxite (A|2O3.2H2O)
are the two
compounds of metals which are found in
minerals

earth.
Ores:

of aluminium.

But aluminium

can

be profitably extracted only from bauxite.
The mineral

from which

a metal

can

Hence

bauxite

is an ore

of aluminium

be readily and economically extracted on and clay is its mineral.

Gold

Aluminium

PERIODIC

12.4.2.

Differences
ats and

o

o

miner-

ux:

OF ELEMENTS

It is the substance

added

to the ore

to reduce the fusion temperature

eres

Minerals contain a low percentage Etegg: It is the fusible product formed
of metal while ores contain a large when flux reacts with gangue during the
extraction
of metals.
percentage of metal.
Flux + Gangue+ Slag
Metals
cannot
be
extracted
easily from mineral. On the other mettteg: Smelting is the process of
hand,ores can be used for the reducing the roasted oxide to metals in
extraction

o

between

CLASSIFICATKDN

All

of metals.

minerals

cannot

the molten
be

called

as

125.

ores,but all ores are minerals.

condition.

QCCURRENCE

GF METALS

Nearly 80 metallic elements are
ttetttgz The process of extracting the obtained from mineral deposits on or
ores from the earth crust is called mining. beneath the surface of the earth.Metals
tttetatturgy: Various steps involved in the which have low chemical reactivity are
extraction

of metals

found in free state, or in native state.

from their ores as well

as refining of crude metal are collectively
Gold, silver and platinum are examples
known as metallurgy.
of metals that are partly found in a free
gangue er Matrix: The rocky impurity, state. Most of the other metals are found
state in the form of their
associated with the ore is called gangue in a combined
oxide ores, carbonate ores, halide ores,

or matrix.

sulphide ores, sulphate ores and so on.

Bauxite

HalideOres
sulphide ores
Cryolite(Na3AlF6) Galena(PbS)

Marble(CaCO3)

(Al 0 .2H 0)
Cuprite (Cu O)
Haematite (Fe O)

Magnesite (MgCO )
Siderite (FeCO )

Fiow Chart (Extraction

Fluorspar (CaF)
Rock salt (Nacl)

Iron pyrite (FeS)
Zinc blende (ZnS)

of Metal from its ore)

@333
V Gravity
separation,
Froth
floatation,
Magnetic
separation, Leaching

lElectro|VytiVc
reduction
refining

calcrnationi
Roasting
Reduction Refining

V

Roasting
Reduction Refining

V

12.6. METALLURGY

OF

ALUMINIUM, COPPER AND
IRON

The conversion of Bauxite into Alumina

12.6.1. Metallurgy

of aluminium

involves the following steps:
i.Bauxite ore is finely grounded and
heated under pressure with concentrated
caustic

soda

solution

at 150°C

to obtain

sodium
meta
aluminate.
150°C

Al2O3.2H2O
+ 2NaOH » 2NaA|O2+ 3H2O
Bauxite

Sodium Meta
aluminate

ii.On diluting sodium meta aluminate with

symboi ; A]

water,aluminiumhydroxideprecipitateis

Colour: Silverywhite

°btai9d-

Atomic number=13

NaAlO2
+2H2O
» NaOH
+A|(OH)3

Electronic
configuration:2,

iii.The precipitate is filtered, washed, dried
and ignited at 1000°C to get alumina.

8, 3

Va&#39;e"°V
=3
Atomic

mass

2Al(OH)3
°°°°AIZO3
+3H2O

: 27

Aluminium is produced by the electro-

_ Aluminium
isthem95t
a_b_dat
m"_ta&#39;
lyticreduction
offused
alumina
(AIZO3)
in

in theearths
crust.Sinceit is a reactivetheelectrolytic
ee"_

metalit occurs
in thecombined
state.eaihede
: Imntanklined
withgraphite

Theimportant
oresof aluminium
areas emea

: A bunch of graphite rods
suspended in molten electrolyte
Eteettetyte : Pure alumina + molten

follows:

Name
Ofetheyorei
A

cryolite
+fluorspar
(fluorspar
lowers
the

A|2O3_2H2O fusion
temperature
ofelectrolyte)
Cryote

Na3A":6

Temperature
: 900-950°C
WW

W:

5&#39;

The overall equation for aluminium extraction is

2Al2O3» 4A| + 302
Extraction

of aluminium

involvestwo stages:

from

bauxite

Aluminium deposits at cathode and
oxygen gas is liberated at anode

PERIODIC

CLASSIFICATION

OF ELEMENTS

Graphitelined iron

l tank

7;;graphite
rods
__., graphite
rod_s_

Refined
aluminium

/
Fig 12.1 Electrolytic rening of aluminium

Properties

of Aluminium

i. It is a silvery white metal.
ii. It has low density and it is light
iii.|t is malleable

and ductile.

iv. It is a good conductor of heat and
electricity.

very brightly forming its oxide and nitride.

4Al + 302 > 2A|2O3(AluminiumOxide)
2Ai + N2» 2A|N (AluminiumNitride)
2.

Reeeiien

with

weier:

Water

has

no

reaction on aluminium due to the layer of
oxide on it.When steam is passed over
red hot aluminium, hydrogen is produced.

2A| + 3H2O> AIQO3+ 3H2T

SteamAluminium
Oxide

3 eaciieri

with

aiiiaiisz

It reacts

with

strong caustic alkalis forming aluminates.

2Al + 2NaOH+ 2H2O> 2NaAlO2 + 3H2T
Sodium meta
aluminate

Fig. 12.2 Electric conductivity of metal

it Reactieii
with acids:
With
v. Melting point: 660°C
vi. It can be well polished to produce con. HCI it liberatesH2gas.
attractive shiny appearance.
2Al + 6HCl > 2AlCl3 + 3H2T

dilute

and

Aluminium

i. iieectieri wiiii air: It is not affected by dry
air.On heating at 800°C,a|uminium burns

Chloride
Aluminium liberates hydrogen on
reaction with dilute sulphuric acid.Sulphur
dioxide

is liberated

sulphuric acid.

with

hot concentrated

2Al+3H,so,»Al2(SO4)3
+3H2T
Dilute

INDUSTRIAL
VISIT
Make
anindustrial
visit
to

2Al+ 6H2SO4
» A|2(SO4)3
+ 6H2O+330;
hot& conc.

Aluminium

Sulphuric acid

Sulphate

MORE

theptace
where
Thermite
Welding
is
aCtUaY
done and record your
observations on joining
the gap between the

TO KNOW

broken pieces of rails.

Fig 12.3

12.6.2 Metallurgy

5. Reducing

actimt

of Copper

: Aluminium is a

powerful reducingagent. When a mixtureof
aluminium powder and iron oxide is ignited,
the latter is reducedto metal.This process is
known as aluminothermicprocess.

Fe2O3+ 2Al > 2Fe + AIZO3

1.Household
utensils

2.Electrical
cable
industry
, .

Aluminium
3.Aeroplanes
metal
. A 9
and
other

Symbol : Cu
Atomic
Atomic

mass : 63.55
number
: 29

Electronic

configuration :2, 8, 18, 1
Valency : 1 and 2

it is light, cheap, cor-

industrial parts
Aluminium
wires

rosion resistant, and

good conductor of

Qccurrence:

It was named as cuprum

ERIODIC

CLASSlF|CATlON

OF ELElVl"NTS

t.$§&#39;t,2$%tErsg
and cetzcentratéoz
The
solution pure copper gets deposited at the
ore is crushed and then concentrated by cathode, impurities settled at the bottom
froth~floatationprocess.
of the anode in the form of sludge called
:.»::,east§ng: The

concentrated

ore

is

attests

mud.

roasted in excess of air. During roasting,
i.moisture and volatile impurities are

Physical properties: Copper is a reddish
brown metal, with high lustre, high density
ii.copper pyrite is partly converted into and high melting point (135600).
sulphides of copper and iron.
Chemical properties:
removed.

2CuFeS2+ o, M»Cu2S+ 2FeS + so,
f%,;%;me§t§:2g:
The roasted ore is mixed with

powdered coke and sand and is heated in
a blast furnace to obtain matte and slag.

§.§3t£%§®§§
at air and moisture: Copper
gets covered with a green layer of basic

copper carbonatein the presenceof CO2
and moisture.

(Matte: Cu2S+FeS)The slag is removed 2Cu + o, + co, + H20 s CuCO3.Cu(OH)2
ti. tctéen at tteat: On heating at different
temperatures in the presence of oxygen it

as a waste.

é~,Besaeme§§aat§m;:
transferred

The

to Bessemer

molten

matte

converter

is

forms two types of oxides CuO, Cu2O.

in order

below
1370K

to obtain blister copper. Ferrous sulphide 2Cu+ C2~->
from

matte

is oxidised

to

ferrous

oxide

which is removed as slag using silica.

2Cu2S+ 302 > 2Cu2O + 2802
2Cu2O+ Cu2S> 6Cu + S02
FeO+SiO2> FeSiO3(Iron silicate,slag)

4Cu+ 02
at. atten

2CuO(copperll oxideblack)

2Cu2O
(copper
l oxidered)
oi? aside:

a) with dil.HCl and dil.H2SO4
Dilute acids such as HCl and H2804

atintrtg:
Blister copper contains 98°/o have no action on these metals in the abpure copper and 2% impurities and are sence of air. Copper dissolves in these
acids in the presence of air.
purified by electrolytic refining.

2Cu + 4HCl + 02 (air) > 2CuCl2 + 2H2O
2Cu + 2H2so, + 02 (air)» 2CuSO4+ 2H2O

This method is used to get metal of high
degree of purity. For electrolytic refining of b) with dil.HNO3Copper reacts with dil.
copper,

we use

Cathode: A thin plate of pure copper
metal.

HNO3with the liberation of Nitric Oxide
gas.

3Cu + 8HNO3(dil)» 3Cu(NO3)2
+ ZNOT+ 4H2O

c) with con.HN03 and con.H2S04
Copper reacts with con. HNO3and con.
Copper sulphate solution H2804 with the liberation of nitrogen

siarmezA block of impure copper metal.
Eiectreiyte:

acidified with sulphuric acid. When electric

dioxide and sulphur dioxide respectively.
+ 2NO2T+ 2H2O
current is passed through the electrolytic Cu + 4HNO3a Cu(NO3)2
(conc.)

Cu + 2H2SO4s CuSO4+ so; + 2H2O
(conc.)

iv.

teticn

Iron

of

{::§t§$§§?%§:Chlorine

reacts

with copper, resulting in the formation of
copper (ll) chloride.

metal

is
after

the

second

aluminium.

ii.Magnetite
iii.|ron pyrites

FeS

It is extensively used for making
electric

cables

appliances.
It is used

and

for

other

making

electric

utensils,

containers, calorimeters, coins.

-

in nature

haematite

:5..&ct§en of atkatiez Copper is not attacked by alkalis.

-

It occurs

abundant

as oxides, sulphides and carbonates. The
ores of iron are given in the following table:

Cu + C|2> CuCl2

-

most

t.£.3oncr3r:t:at%o:&#39;2
by gravity sepe.ratic:2

The powdered ore is washed with
It is used in electroplating.
stream
of water. As a result, the lighter
It is alloyed with gold and silver for
sand particles and other impurities are
making coins and jewels.
washed away and heavier ore particles

A

students

settle

down.

Eeaszgténgand ca%c§nat:c>:t

askedlto
important
applicationsofcopper everyday
. {;,l:ife
alongswithfther
sampIes...,,rii.*i
T

furnace. As a result, moisture is driven

12.6.3
METALLURGY
OFERON

out and sulphur, arsenic, phosphorus
impurities are oxidised off.

The concentrated ore is strongly heated
in a limited supply of air in a reverberatory

r

17

:

,,.=,E5me%i:§n§g
{in attestfurnace;
The charge consisting of roasted ore,
coke

Symbol
Colour
Atomic
Atomic

:
mass

Fe
Greyish white
55.9

number:

26

Valency

2&3

in the ratio 8 : 4 : 1 is

smelted in a blast furnace by introducing
it through the cup and cone arrangement
at the top. There are three important
regions in the furnance.
i.The lower region(combustion

zone)-

temperature is at 150000.
In this region, coke burns with oxygen

to form CO2when the charge comes in

Electronic

configuration

and limestone

:

2, 8, 14, 2

contact

with the hot blast

of air.

PERIODIC

CLASSIFICATION

OF ELEMENTS

The iron thus formed is called pig

1500°C

C + 02 Z)

CO2 + heat

It is an exothermic

reaction

iron.
since

heat

It is remelted

moulds.

is liberated.

This

and cast

iron is called

into different

cast

MORE

TO KNOW

MORE

TO KNOW

iron.

ii.The middle region (fusion zone)The
temperature prevails at 1000°C.ln this

regionCO2is reducedto CO.
1000°C

CO2+ C >

2CO

Limestone decomposes to calcium

oxide and CO2.
CaCO3>
These

A
two

CaO + CD2
reactions

are

endothermic

due to the absorption of heat. Calcium
oxide

combines

with silica

to form calcium

silicate slag.

CaO + SiO2 » CaSiO3
iii.The upper region (reduction

zone)-

temperature prevails at 400°C. In this
region carbon monoxide reduces ferric
oxide to form a fairly pure spongy iron.

Fe2O3+ 3C0 >
The

molten

400°C

2Fe + 3CO2

iron is collected

at the bot-

tom of the furnaceafter removingthe slag.
be/I& hopper

7*

Physical properties
Iron ore,
T coke

-

Pipe for

It is a heavy metal of specific gravity
7.9 g/cc
It is a lustrous metal and greyish white
in colour.

Slag outlet

.
Fig. 12.4 Blast furnace

Ironout/et

-

It has high tensility, malleability and
ductility.
It is a good conductor of heat and
electricity.
It can be magnetised.

E..ReaotEort
wgtiiasoroxygen:
Onlyon
heating in air, iron forms magnetic oxide

3Fe + 202 > Fe3O4(black)
Eeacticn

with

moist

air:

When

iron is

exposed to moist air, it forms a layer of
brown hydrated ferric oxide on its surface.
This compound is known as rust and the
phenomenon of forming this rust is known
as rusting.

buildings, machinery, transmission and
T.V towers and in making alloys.
iii.Wrought iron is used in making
springs, anchors and electromagnets.
12.7 ALLOYS

An allo is a homogeneous mixture of
of a meta

with

other

metals

or with

non-

metals that are fused together.
Attoys are solid soiutions. Alloys can be
considered

as solid

solutions

in which

the

metal with high concentration is solvent

4Fe + 302 + 3H2O> 2Fe2O3.3H2O(Rust)and
(Moisture)

Eeaetiort

wtth

steam;

When

steam

is

passed over red hot iron,magnetic oxide

the

metal

with

low

concentration

of iron is formed.

12.7.1 Methods of making alloys:

3Fe + 4H2O(steam)> Fe3O4+ 4H2T

1.By fusing the metals together.
2.By compressing finely divided metals

faeacttort

with

with chlorine

chtmine:

to form

Iron combines

ferric

one over the other.

chloride.

2Fe + 3C|2> 2FeC|3(ferricchloride)
Seaction

with

acids:

With

dilute

HCI

and dilute H2804it evolves H2gas
Fe + H2804> FeSO4+ HZT
With conc. H2804it forms ferric sulphate
2Fe + 6H,so, > Fe2(SO4)3
+ 3so2 + 6H2O

With dilute HNO3in cold conditionit gives
nitrate

4Fe + 10HNO3+ 4Fe(NO3)2+ NH4NO3
+ 3H2O

when iron is dipped in come. §-tN{}3it
becomes chemically inert or passive
due to the formation of a layer of iron ox-

ide (Fe3O4)on its surface.
§.%Fsg
wereis used in making pipes, stoves,
radiators, railings, man hole covers and
drain pipes.
ii. teret

is used

in the

construction

.tmaEgam:An amalgam is an alloy of
mercury with metals such as sodium,
gold, silver, etc.,
MORE

Fe + 2HC| > FeC|2 + HZT

ferrous

is

solute. For example, brass is an alloy of
zinc(solute) in copper(solvent).

of

TO KNOW

I PERIODIC

CLASSIFICATION

OF ELEMENTS

12.7.2 Copper Alleys
Name of the alloy

Reason for alloying

i.Brass(Cu,Zn)

Lusturous,easily

Electrical fittings, medals, hard

cast,malleable,

ware, decorative items.

ductile,harder

than Cu.

ii.Bronze(Cu,Sn,Zn)

12.7.3 Aluminium

Hard,brittle,takesup polish.

Statues, coins, belis, gongs.

Alloys

Name of the alloy

Reason for alloying

i.Duralumin(Al,Mg,Mn,Cu)

Light,strong,resistant to corrosion
stronger than aluminiu m.
Light,hard,tough,corrosion resistant.

ii.Mag nalium(Al,Mg)

Aircraft,tools,pressure
cookers
Aircraft,scientific instrument

12.7.4 iron Alloys
Name of the alloy

Reason for alloying

i.Stainlesssteel (Fe,C,Ni,Cr) Lusturous,corrosion resistant,high
tensile strength.
ii.Nickel steel (Fe,C,Ni)
Hard, corrosion resistant,eiastic.

12.3CORROSION
Corrosion

is defined

ME
as the slow

steady destruction of a metal
environment.

It results

Utensils,cutlery,automobile
parts.
Cables,aircraft parts,propeiler.

and

by the

in the deterioration

of the metal to form metal compounds
by means of chemical reactions with the
environment.

Water
droplet

IRON

Busting of iron

TO KNOW

ACTIVITY 12.1 A

Theconditionsfor rusting
Take three test tubes provided with rubber corks and label them as A, B and C.

Placefew ironnailsof samesizein thesetubes.Poursomewaterin testtubeA, a
some boiled water along with turpentineoil in test tube B and anhydrousCaCl2
in test tube C.Keepthem underobservationfor few days. Noticethe changes.

ThenailsinAarerusted
whilethe nailsin BandCareunaffected.

Therusting
ofnails
inAisduetoairandwater.
InB,theoilylayer
above
water
does not allow air to come in contactwith nails. In C, the substanceanhydrous

CaCI2
hasabsorbed
moisture
completely.
Thisactivityshowsthatrustingof iron
requiresair and water.
Methods of preventing

corrosion:

Corrosion of metals is prevented by
not allowing them to come in contact with

moisture,CO2and O2.Thisis achievedby
the following methods:
9

S}; coating with paints: Paint coated metal
surfaces keep out air and moisture.
By coating with eii and grease: Application
of oil and grease on the surface of iron tools
prevents them from moisture and air.
83; aiieying with other meiais: Alloyed metal
is more resistant

to corrosion.

Exampie: stainless steel.
By the process of gaivanizatieni This is a
process of coating zinc on iron sheets by using
electric current. In this zinc forms a protective
layer of zinc carbonate on the surface of iron.
This prevents corrosion.
Eiectmpéatirtgz It is a method of coating one
metal with another by passing electric current.
Example: silver plating, nickel plating. This
method not only lends protection but also
enhances the metallic appearance.
Saprificiai protection: Magnesium is more
reactive
articles

than iron. When it is coated on the
made of steel it sacrifices
itself to

protect the steel.

PERIODIC

CLASSIFICATEON

OF ELEMENTS

EVALUATEGN
PART

- A

1. In the modern periodic table periods
and groups are given. Periods
and
groups
indicate
a) Rows and Columns b) Columns
and rows

2. Third period contains 8 elements, out
of these elements how many elements
are nonmetals?.
3. An

element

which

is

an

essential

constituent of all organic compounds
belongs to
group.
(14* group/ 15 group)
4. Ore

is

used

for

the

extraction

(froth floation / gravity separation)
8. Coating the surface of iron with other
metal prevents it from rusting. If it is
coated with thin layer of zinc it is called
T
(galvanization / painting /
cathodic protection)
.Any metal mixed with mercury is
called amalgam. The amalgam
used for dental filling ls
.
(Ag Sn amalgam /Cu Sn amalgam)
A .

In

thermite

welding,

aluminium powder and Fe2O3are
used. Reason: Aluminium powder is
a strong reducing agent. Does the
reason satisfy the assertion?

of

metals profitably. Bauxite is used to
extract aluminium, it can be termed as

. (ore / mineral)
5. Gold

does

not occur

PART

in the combined

form. It does not react with air (or)
water. It is in
. (native state /
combined state)
PART

11 .

12.

- B

It is due

to the

formation

13.

of

Give your correct option
a) assertion and reason are correct
and relevant

to each

14.

reacts

with

with coke?
con.

HCI

and

con.

with proper reason.
To design the body of the aircraft
aluminium alloys are used. Give
your

other

b) assertion is true but reason is not

Iron

oxide

HZSO4.But it does not react with
con. HNO3. Suggest your answer

layer of basic copper carbonate

relevant

Can rusting of iron nail occur in
distilled water. Justify your answer.
Why cannot aluminium metal
be obtained by the reduction of
aluminium

..
Greenish layer appears on
copper vessels if left uncleaned.
Reason:

- C

15.

to the assertion

7.A
process employed for the
concentration of sulphide ore is

reason.

X is a silvery white metal. X reacts
with oxygen to form Y. The same
compound is obtained from the
metal

on reaction

with steam

with the

liberation of hydrogen gas. Identify X
and Y.

FURTHER
F1IEFEl&#39;-CIENCE:
&#39;

Books:
.TextBook
oflnorganicchemistry
P.L_§3oni(S.CnandPublishers.
~
1Website:www.tutorvista.com.
www.sciencebyjones.com
.

CARBON

AND

ITS COMPOUNDS

13.Carbon and its compounds
Symbol
Atomic

Number:

Atomic

Mass

Valency

The electronic configuration of carbon
is

K=2, L=4. It has four electrons

in the

valence shell and belongs to group IV A
(group 14) of the periodic table.

INTRODUCTION
Without carbon, no living thing could
survive. Human beings are made up of
carbon compounds. Carbon is a non
metal. In nature, it occurs in its pure form

as diamond and graphite. When fuels
burn,

the

carbon

in them

reacts

with

oxygen to form carbon dioxide.
Carbon compounds hold the key to
plant and animal life on earth. Hence,

carbon chemistry is called Living
Chemistry. Carbon circulates through
Fig. 13. 1 electronic
conguration of carbon

air, plants, animals and soil by means of
complex reactions. This is called carbon

cycle.
13.1. COMPOUNDS
CARBON

OF

In the beginning of 19th centuryscientists
classified the compoundsof carbon into two
types, based on their source of occurence:
i) Inorganic compounds (obtained from
non living matter)
ii) Organic compounds (obtained from
living matter, such as plant and
animal sources) however the basis
Fig. 13.2 An arrangement depicting carbon
and its compounds.

of classification was subjected to
alteration after wohler synthesis.

LIVING

CHEMISTRY

All living organisms are made of carbon atoms. This means that, carbon atoms
form the building blocks for living organisms. These carbon atoms, in combination with

other atoms decide life on earth. Hence carbon chemistry is also called as living
chemistry.

""5 .

Fig.
13.3

L Fig. :H
FRIEDRICH

A creator

of revolution

WOHLER
in ORGANIC

CHEMISTRY

MORETO ow

brniusm
bl

to

CARBON

13.2. MSDERN
DEFINITION
OF
QRGANIC
CHEMISTRY
Organic chemistry is defined as the
branch of chemistry that deals with organic compounds which are made up of
the hydrocarbons and their derivatives. It
gives a thorough insight into the nature of
bonding, synthesis, characteristics and
their

usefulness

in various

MORE

TO KNOW

fields.

AND

lTS COMPOUNDS

13.3. BONDING

lN CARBON

AND HTS COMPOUNDS
The

atomic

number

of carbon

is 6 and

its ground state electronic configuration
is 1s22s2 2p2. Since it has four electrons
in its outermost shell, its valency is four.

To achieve noble gas configuration,
carbon atom has to lose or gain four
electrons

to form

C

and C4 ions.

1. It could gain four electrons forming C4
anion, but it would be difficult for the
nucleus with six protons to hold on to
ten electrons
2.

It could

i.e.four

lose four

extra

electrons

electrons.
to form

C

cations, but it would require a large
amount of energy to remove four
electrons leaving behind the carbon
cations with six protons in its nucleus
holding on to just two electrons.
Carbon overcomes this problem by
sharing its valence electrons with other
atoms

of carbon

elements.

This

or with

atoms

characteristic

of other
of

carbon

atom by virtue of which it forms four
covalent bonds is generally referred as

tetra valency of carbon.

A moleculeof methane(CH4)is formed
when

four

electrons

of carbon

are shared

with four hydrogen atoms.

Fig. 13.5 Structure of methane
0 0 Represents shared pair of electrons

13.4 ALLQTRGPY
Allotropy is defined as the property by
which

an element

can

exist

in more

than

Since this looks like the geodesic
dome designed by the US architect
Buck
Buck

Minster
Minster

Fuller,

it is named

as

Fullerene.

one form that are physically different but
chemically similar.

Carbon exists in three allotropic forms.
They are crystalline form (diamond
and
graphite),

(coke,charcoa|)

......
--

...,_
,1,u

....... _ _

andfullerene. §::1Z&#39;.&#39;.
......

.-

Fig. 13.8 Fullerene

,.

13.5 Physicat nature of carbonand

Indiamondeach

its compounds

carbonatomis
bonded to four

nu."

other carbonA------

.;

atoms forming ..............
a

rigid

three

dimensional

of diamond

structure,

In graphite
bonded

for

its

hardness

and

has

the

covalent

bonds

ability

with

other

to

form

atoms

of

catenation.

Since the valency of

carbon is four, it is capable of bonding
each

to three

carbon

other

atom

carbon

is

atoms

in the same plane giving hexagonal

layers held together by weak vander
Waals forces accounting for softness.
Graphite is a good conductor of
electricity unlike other non-metals
since

Carbon

:

carbon giving rise to large number
of molecules through self linking
property This property
is called

Fig_13_6
Structure

accounting
rigidity.

Fig. 13.9 Foot ball

it has free electrons
vander

with

four

Waals

foroe

atoms.

Carbon
combines
with
oxygen,
hydrogen, nitrogen, sulphur, chlorine
and many other elements to form
various stable compounds.
The stability of carbon compounds is
due to the small
enables

in it.

other

size

the nucleus

of carbon
to hold

which

on to the

shared pair of electrons strongly.
Carbon
compounds
show

isomerism,

the

phenomenon

whichtwoormorecompoundsto
same

molecular

structural

formula

formula
with

by

have

but different
difference

in

properties. i.e the formula C2H6O
O

0

Fig. 13.7 Structure of graphite

Fullerenes form another type of
carbon allotropes. The first one was
identified

to contain

60 carbon

in the shape of a football.

atoms

(C-60).

represents

two different compounds

namely ethyl alcohol (C2H5OH)and
dimethyl ether (CH3OCH3).
Carbon compounds have low melting
and boiling points because of their
covalent

nature.

CARBON

o

AND

ITS COMPOUNDS

The reactions shown by carbon
compounds involve breaking of old
bonds in the reacting molecules and
the

formation

of

new

bonds

in

the

product molecules.
o

Carbon

compounds

combustible.

13.? HOMQLOGDUS

13.6 CHEMICAL.
o

PROPERTIES

are burn
easily
Carbon and its compounds
in
oxygen to give carbon dioxide along
with heat and light.

e.g.,

A homologous series is a group or a
class oforganic compounds having similar
structure and similar chemical properties
in which the successive compounds differ

by a CH2group.
13.7.1

Characteristics

C+02>CO2+
heat
+light
o

compounds

can

member

(amu = atomic mass unit).
o

All members
contain

undergo

carbon

addition

compounds

reactions

o All members

series

and the same

of homologous

series

have same general molecular formula.

e.g Alkane = CnH2n22

e.g.,

Alkene = CnH2n
Alkyne = CnH2n-2

Addition
ofhydrogen
CH2= CH 2

>CH2 - CH2

Ethene

Ni-catalyst

substitution

reaction

to form

different

types of products.
Carbon compounds such as alcohols
with

sodium

o

to

liberate

The members in homologous series
show a regular gradation in their
physical properties with respect to

Ethane

Carbon
compounds
undergo
substitution reactions in the presence
of either sunlight or any other
reagents. e.g., methane undergoes

react

of homologous
elements

functional groups.

or nickel catalyst.

o

same

with

hydrogen in the presence of palladium

o

from

to

form carboxylic acids.
Unsaturated

differs

and by a molecular mass of 14 amu

oxidized using suitable oxidizing agent

0

of the series

by a common difference of CH2

be easily

Alkaline potassium permanganate

Each

series

the preceeding or succeeding member

C2H5OH
+ 202» 2Co2+3H2O+ heat+ light
Carbon

of

homologous

CH2 + 2o2 > CO2+ 2H2o + heat + light

o

SEREES

increase

o

in molecular

mass.

The chemical
properties
of the
members of the homologous series
are similar.

o All members of
can

be

prepared

homologous

series

by using

same

13.8 IMPORTANCE
GF
HOMOLOGQUS
SERIES

Formula

1. It helps to predict the properties of the
members of the series that are yet to
be prepared.

CH

Common

IUPAC

name

name

Methane

2. Knowledge of homologous series gives
a systematic study of the members.

Ethane
Methane

3. The nature of any member of the family can be ascertained if the properties
of the first member

simplest

containing

only

CH3CH3

organic
carbon

compounds

and hydrogen

Ethane

Butane

4

13.9 HYDROCARBONS
The

Propane

are known.

CH3CH2CH3 Propane
CH3CH2CH2CH3
nButane

are called Hydrocarbons. These are
regarded as the parent organic compounds and all other compounds are

13.9.2 Unsaturated

considered to be derived from them by
the replacement of one or more hydrogen

carbon
tocarbon
double
bonds
3;
{1}}

atoms by other atoms or groups of atoms.

or carbon to carbon triple bonds -CEC-

hydrocarbons

These are hydrocarbonswhich contain

in

their

molecu|es.These

are

further

Hydro carbons are classified into two classified into two types: atalkerresand
types: saturated and unsaturated hydro- etkynes.
carbons.
i)AIkenes GeneralformuIa:Cn2n
H Su&#39;ix:ene
13.9.1 Saturated hydrocarbons

The hydrocarbons containing atleast one

-

carbon

Alkanes

General formula = CnH2n+2Suffix
: ane
These are the organic compounds
which contain carbon
carbon single
bond.These

were

paraffins(Latin
due to their

earlier

named

as

: meaning little affinity)
least chemical

reactivity.

According to IUPAC system, these are
named as alkanes (ane is suffix with
root word).

to carbon

double

bond

are called

alkenes.They have the general formula
CnH2n.These were previously called
olens (Greek : olefiant
oil forming)
because the lower gaseous members of
the family form oily products when treated
with

chlorine.

In IUPAC system, the name of alkene
is derived by replacing suffix ane of the
correspding alkane by ene.For example,

CH3 CH3
ethane

HZC= CH2
ethene

= CARBON

AND

lTS COMPOUNDS

In higher alkenes, the position of the double bond, can be indicated by assigning
numbers 1, 2, 3, 4, .... ..to the carbon atoms present in the molecule.

CH2= CH2

Ethylene

Ethene

CHSCH= CH2

CH3CH2-CH=CH2
F|0l3Y&#39;9|"|e Propene

CH3CH
=CHCH3

But-1ene

But-2ene
d-l3utylene

BButy|ene
ii) Alkynes: Generalformula:CnH2n_2Suffix:yne
The hydrocarbonscontainingcarbon to carbon triple bond are called §.§{jV§§@$.
Alkynesare named in the same way as alkenes i.e., by replacingsuffixane of alkane
by yne. In higher members, the position of triple bond is indicated by giving numbers
1, 2, 3, 4, ....to the carbon atom in the molecule.

AI AAlkynef?
s

to Common
name

AIUPAC.name

HCEACH
AA A

Acetylene

Ethyne
AA

H3C C ECH

Methylacetylene

Propyne

H3C C EC CH3

Dimethylacetylene

But2yne

H3C CH2C E CH

Ethylacetylene

But1yne

13.10.

FUNCNQNAL

GROUP

Functional group may be defined as an atom or group of atoms or reactive
part which is responsible for the characteristic properties of the compounds.
The chemical properties of organic compounds are determined by the functional
groups while their physical propertiesare determined by the remaining part of the
molecule.

Example: -OH => Alcohol
CHO

=> Aldehyde

)C=O => Ketone
- COOH

=> Carboxylic acid

CH3-CH2-OH
T

Ethyl
alcohol

Ethanol

CH3CH2-CH2-OH
t

n-Propyl
alcohol

1-Propanol

CH3-CH-CH3lsopropyl
alcohol T 2-Propanol
-IOH

orsecondary
propyl
alcohol

CH3CH2-CH2-CH2-OH
n-Butyl
alcohol
CH3-CH-CH2-OH

a

lsobutyl alcohol a

T

V 1-Butanol
2-Methyl-1-propanol

l

Aldehydes are carbon compounds containing -CHO group attached to alkyl
group or hydrogen atom. The general formula of aldehydes is R CHO where
R is an alkyl group or hydrogen atom and
CHO is the functional group.
The IUPAC name of aldehyde is derived by replacing e, in the word alkane,
by the suffix al. Hence we get the name alkanal.
HCHO

T

CH3CH0

CH3
CH2-CH0

V Formaldehyde

T

Methanal

V

V AcetaldehydeT Ethanal

Propionaldehyde
. Propanal
l

CH3-CH2-CH2-CH0
Butyraldehyde Butanal
3. Ketones

Ketones are carbon compounds containing carbonyl CO
group attached
to two alkyl groups. The general formula of ketone is R-CO-R where R and
R are alkyl groups and
CO is the functional group. The IUPAC name
of ketone is derived by replacing e, in the word alkane, by the suffix -one.
Hence we get the name alkanone.

CARBON

AND

ITS COMPOUNDS

CH3COCH3
OL

Dimethyl
ketone
(Acetone)
Propanone

CH3COCH2CH3
V

Ethylmethylketohey2Butanone

CH3CHéCOCH2CH3
Diethylketone
OTO O3Pentanone

4. Carboxylic

Acids

Carboxylic acids are carbon compounds containing COOH group attached
to a hydrogen atom or alkyl group. The general formula of acid is R-COOH
where R is a hydrogen atom or alkyl group and COOH is the functional
group. The IUPAC name of acid is derived by rep|acinge, in the word alkane, by
the suffix oic acid. Hence we get the name aikanoic acid.

HCOOH

CH3-COOH
.y r

Formic
acid

Methanoic
acid

. Acetic
acid

OEthanoic
acidO

CH3CH2-COOHT

Propionic
acidV

Propanoic
acid

CH3CH2-CH2-COOH
.

n-Butyric
acidV

Butanoic
acid

Almost all the compounds are useful to us in a number of ways. Most of the fuels,
medicines,

paints, explosives,

synthetic

polymers,

perfumes and detergents

are

basically organic compounds. In fact, organic chemistry has made our life colourful
and also comfortable. Two commercially important compounds, ethanol and ethanoic

acid are briefly discussed here.

13.11ETHANOL(C2H50H)
Ethanol or ethyl alcohol or simply alcohol is one of the most important members
of the family of alcohols.

Molasses is a dark coloured syrupy liquid left after the crystallization of sugar from
the concentrated sugar cane juice. Molasses still contain about 30% of sucrose which
cannot be separated by crystallization.

It is converted into ethanol by the following

steps:

ii}iiiiiiaii
Molasses
isfirst
diluted
with
water
tobring
down
the
concentration
ofsugar
to
about 8 to 10 percent.

{iii Amiiieit

oi ammonium

aaiis

Molasses usually contains enough nitrogenous matter to act as food for yeast
during fermentation. If the nitrogen content of the molasses is poor, it may be

fortified by the addition of ammonium sulphate or ammonium phosphate.
{iii} imdiiioii

oi yeasi

The solution from step (ii) is collected in large fermentation tanks and yeast is
added to it. The mixture is kept at about 303K for a few days.During this period,
the enzymes invertase and zymase present in yeast, bring about the conversion
of sucrose

into ethanol.

CHO
122211

+H2oM*_2Se_»cHo+cHo
6126
6126
Giucose

c 6126
H o

E,

Glucose

Fructose

2C2H5OH
+2co2¢
Ethanol

The fermented liquid is technically called wash.
{iii} isiiiiaiioii

iii iiiasii

The fermented liquid containing 15 to 18 percent alcohol and the rest of the water,
is now subjected to fractional distillation. The main fraction drawn, is an aqueous
solution

of ethanol

which

contains

95.5%

of ethanol

and 4.5%

of water.

This

is called

rectified spirit. This mixture is then heated under reflux over quicklime for about 5 to
6 hours and then allowed to stand for 12 hours. On distillation of this mixture, pure
alcohol (100%) is obtained. This is called absolute alcohol.

3 CARBON

AND

ITS COMPOUNDS

(i) Ethanol is a clear liquid with burning taste.
(ii) Its boiling point is 351.5 K which is higher than corresponding alkane.
(iii) It is completely miscible with water in all proportions.

(i) Behydratim

(a) lntra moleculardehydration: Ethanol,
whenheatedwithexcessconc.H2804at
443 K undergoes intra molecular dehydration (i.e. removal of water within a
molecule of ethanol).

Conc.H2SO4

CH3CH2OH
}
Ethanol

CH2=CH2+H2O
Ethene

(b) Intermoleculardehydration
:Whenexcessofa|coho|isheatedwithconc.
H2804
at 413K two molecules condense by losing a molecule of water to form ether
(i.e. removal of water from two molecules of ethanol).

Conc.H2SO4
c 2H5-oa + =o- c2H5

413Kc2H5«o-C2:

5+HO2

e:%%e§

(it) Reaction with sodium

: Ethanol reacts with sodium metal to form sodium

ethoxide and hydrogen gas.

ECEHEGH
+ BN3 +

;?;C3H5ONa+ H23
sodium

ethoxide

(iii) xidation : Ethanol is oxidizedto ethanoicacid with alkalineKMnO4or acidified

K9207

CHSCHZOH
+°"&#39;°&#39;a°
CHSCOOH
+H2O
Ethanoic

acid

Duringthis reaction,orangecolourof K2Cr2O7
changesto green.Therefore,this
reaction

can be used

for the identification

of alcohols.

(iv) Esterificaiton : Ethanolreactswith ethanoicacid in the presenceof conc.H2SO4
(catalyst) to form ethyl ethanoate and water. The compound formed by the reaction
of an alcohol with carboxylic acid is known as ester (fruity smelling compound) and
the reaction

is called

esterification.
conc.H2SO4
E}

Ethanol

E&#39;l305C
acid

Ethylethanoate

(v). Dehydrogenation : When the vapour of ethanol is passed over reduced copper
catalyst at 573 K, it is dehydrogenated to acetaldehyde.
Cu

CH3CH2OH
7+
Ethanol

Ethartl

2
CHSCI-O+H
Acetadehyde

is used

1. as an antifreeze

in automobile

radiators.

2. as a preservative for biological specimen.
3. as an antiseptic to sterilize wounds in hospitals.
4. as a solvent for drugs, oils, fats, perfumes, dyes, etc.
5. in the preparation of methylated spirit (mixture of 95% of ethanol and 5% of methanol),

rectified spirit (mixture of 95.5% of ethanol and 4.5% of water), power alcohol
(mixture of petrol and ethanol) and denatured spirit (ethanol mixed with pyridine).
6. in cough and digestive syrups.

Evil effects at $@§E£%.§§§"%§§"§§§
aimtwi
o If ethanol is consumed, it tends to slow down metabolism of our body
and depresses the central nervous system.
o It causes mental depression and emotional disorder.
0

It affects our health by causing ulcer, high blood pressure, cancer,

o

brain and liver damage.

o Nearly 40% accidents are due to drunken drive.

CARBON

AND

BTS COMPOUNDS

0 Unlike ethanol, intake of methanol in very smallquantities can cause death.
o

Methanol is oxidized to methanal (formaldehyde)

in the liver and methanal

reacts rapidly with the components of cells.
o

Methanal causes the protoplasm to get coagulated, in the same way an egg
is coagulated by cooking. Methanol also affects the optic nerve, causing
blindness.

13.12. ETHANOICACID (CH3COOH)
Ethanoic acid is most commonly known as acetic acid and belongs to a group
of acids called carboxylic acids. Acetic acid is present in many fruits and sour taste of
fruits

is because

of this acid.

Ethanol on oxidation in the presence of alkaline potassium permanganate or

acidified potassium dichromate gives ethanoic acid.

Oxidation

CHECHZOHT»
Ethanol

(i)

¬H3CO®H+:-go
Ethanoic

acid

Ethanoic acid is a colourless liquid and has a sour taste.

(ii) It is miscible with water in all proportions.
(iii) Boiling point (391 K) is higher than corresponding alcohols, aldehydes and
ketones.

(iv) On cooling, pure ethanoic acid is frozen to form ice like flakes. They look like
glaciers, so it is called glacial acetic acid.

(i) Ethanoic acid is a weak acid but it turns blue litmus to red.
(ii) Reaction with metal
Ethanoic acid reactswith metals like Na, K Zn, etc to form metal ethanoate and hydrogen gas.

2CH3COOH+ Zn TD

(CH3COO)2
Zn + HQT

ZCHSCOOH
+ 2Na >

2CH3COONa + HQT

(iii) Reaction with carbonates and bicarbonates.
Ethanoic acid reacts with carbonates and bicarbonates and produces brisk
effervescence

due to the evolution

of carbon

dioxide.

2CH3COOH+ Na2CO3??>

2CH3COONa+ COZT+ H20

CH3COOH+ NaHCO3a>

CH3COONa+ COZT+ H20

(iv) Reaction with base
Ethanoic acid reacts with sodium hydroxide to form sodium ethanoate and water.

(v) Decarboxylation(Removalof CO2)
When sodium salt of ethanoic acid is heated with soda lime (Solid mixure of 3 parts
of NaOH and 1 part of CaO) methane gas is formed.

Cl-l3COOt\la
A

CH4}?
+ Nazcag

1. for making vinegar which is used as a preservative in food and fruitjuices.
2. as a laboratory reagent.
3. for coagulating rubber from latex.
4. in the preparation of dyes, perfumes and medicine.

EVALUATICN
PART

- A

1. Assertion: Chemical bonds in organic compounds are covalent in nature.
Reason: Covalent bond is formed bythe sharing ofelectrons in the bonding atoms.
Does the reason satisfy the given assertion.
2. Assertion:
Diamond
is the
hardest
crystalline
form
of
carbon
Reason: Carbon atoms in diamond are tetrahedral in nature (Verify the suitability
of reason to the given Assertion mentioned above)

CARBON

AND

ITS COMPOUNDS

3.

Assertion: Due to catenation a large number of carbon compounds are formed.
Reason: Carbon compounds show the property of allotropy.
(Is the reason holding good for the given Assertion)

4.

Buckminster fullerene is the allotropic form of (Nitrogen / Carbon / Sulphur)

5.

Eventhough it is a non metal, graphite conducts electricity.

presence of

It is due to the

(free electrons / bonded electrons)

6.

Formulaof methaneis CH4 and its succeedingmemberethane is expressed
in CZH6.The commondifferenceof successionbetweenthem is (CH2/ C2H2)

7.

IUPAC name of first member of alkyne is

8.

Out of ketonic and aldehydic group which is the terminal functional group?

9.

Acetic acid is heated with a solid X kept in a test tube. A colourless and
odourless gas (Y) is evolved. The gas turns lime water milky when passed
through it. Identify X and Y.

10.

Assertion: Denaturation of ethyl alcohol makes it unfit for drinking purposes.

(ethene / ethyne)

Reason: Denaturation of ethyl alcohol is carried out by methyl alcohol.
Check

PART

11.

whether

the reason

is correct

for assertion.

- B

Write down the possible isomers and give their IUPAC names using the

formula C4H,0.
12.

Diamond is the hardest allotrope of Carbon. Give reason for its hardness.

13.

An organic compound (A) is widely used as a preservatives in pickles and has a

molecularformula C2H4O2.This compoundreactswith ethanolto form a sweet
smelling compound (B).
(i) Identify the compound A and

B.

(ii) Name the process and write corresponding chemical equation.

14. An organiccompound(A) of molecularformulaC2H6Oon oxidationwith alkaline
KMnO4 solution gives an acid (B) with the same number of carbon atoms.
Compound A is used as an antiseptic to sterilize wounds in hospitals. ldentifyA
and B. Write the chemical equation involved in the formation of B from A.

PART

- C

15. Fill in the blanks using suitable formula in the given table

C2H6 ethane

Propane

16. Homologous series predict the properties of the members of hydrocarbon.
Justify this statement through its characteristics.

17. Write the common name and IUPAC name of the following.

a) CH3CH2CHO

b) CH3COCH3

c)CH3ClHCH3

d) CH3COOH

OH

e) HCHO

FURTHER
REFERENCE
Books:P
1.0raganicchiemistryl
8.3.7
Baht
&Arun
Baht
S.ChanVd
Publishers
. PE
t P2.0rganic
chemistryf
Bil".Morrision
&RN.Boyd
-Practice
Hallat
Publishers.

P E

g P

P

PEV

Er

E

Website;lwww.tutorvista.com,
www.topperlearning.comP