CBSE Test Paper - 01 CLASS - XII Chemistry (Surface chemistry) Answers Class 12 Notes | EduRev

Class 12 : CBSE Test Paper - 01 CLASS - XII Chemistry (Surface chemistry) Answers Class 12 Notes | EduRev

 Page 1


CBSE TEST PAPER-01 
CLASS - XII CHEMISTRY (Surface chemistry) 
Topic: Adsorption – types and nature 
ANSWERS 
1. The accumulation of molecular species at the surface rather than in bulk of a solid liquid
is termed as Adsorption.
2. The molecular species which get concentrated or accumulated at the surface are
adsorbate and the material on the surface of which the adsorption takes place is
adsorbent.
3. Adsorbate examples O 2, H 2, CO, Cl 2, NH 3 etc.
Adsorbent examples – charcoal, silica gel, alumina gel, clay, colloid etc.
4. The process of removing an adsorbed substance from a surface on which it is adsorbed is
called desorption.
5. Adsorption Absorption 
1. It occurs on the surface of the 1. The molecules of the substance are
Adsorbent. uniformly distributed throughout the body
of the solid or liquid.
2. Rate of adsorption decreases until 2. Rate of absorption is same throughout.
the equilibrium is reached .
6. Powdering of solids increase its surface and therefore it can adsorb a greater amount of
the adsorbate. Thus finely divided solids act as good adsorbents.
7. Two types of adsorptions are –
1. Physical adsorption or physisorption .
Page 2


CBSE TEST PAPER-01 
CLASS - XII CHEMISTRY (Surface chemistry) 
Topic: Adsorption – types and nature 
ANSWERS 
1. The accumulation of molecular species at the surface rather than in bulk of a solid liquid
is termed as Adsorption.
2. The molecular species which get concentrated or accumulated at the surface are
adsorbate and the material on the surface of which the adsorption takes place is
adsorbent.
3. Adsorbate examples O 2, H 2, CO, Cl 2, NH 3 etc.
Adsorbent examples – charcoal, silica gel, alumina gel, clay, colloid etc.
4. The process of removing an adsorbed substance from a surface on which it is adsorbed is
called desorption.
5. Adsorption Absorption 
1. It occurs on the surface of the 1. The molecules of the substance are
Adsorbent. uniformly distributed throughout the body
of the solid or liquid.
2. Rate of adsorption decreases until 2. Rate of absorption is same throughout.
the equilibrium is reached .
6. Powdering of solids increase its surface and therefore it can adsorb a greater amount of
the adsorbate. Thus finely divided solids act as good adsorbents.
7. Two types of adsorptions are –
1. Physical adsorption or physisorption .
2. Chemical adsorption or chemisorption .
8. Physical Adsorption Chemical Adsorption 
1. It is caused by Vander Waals forces. 1. It is caused by chemical bond formation.
2. It is not specific in nature. 2. It is highly specific in nature.
3. It is reversible in nature. 3. It is irreversible.
4. Enthalpy of adsorption is low. 4. Enthalpy of adsorption is high.
9. During adsorption, there is always a decrease in residual forces of the surface. Therefore
the surface energy decreases which appears as heat. Therefore adsorption is exothermic
process.
10. Adsorption arises due to presence of unbalanced forces or residual attractive forces on
the particles of the surface. These forces are responsible for attracting the adsorbate
particles on its surface and they cause the adsorption.
11. H ? is negative, S ? is negative and G ? is negative.
12. (a) Ammonia gets adsorbed more readily because it is polar molecule and easily
liquifiable. 
 (b) Charcoal powder adsorbs more of carbon monoxide because it has larger surface area 
than charcoal lump. 
Read More
Offer running on EduRev: Apply code STAYHOME200 to get INR 200 off on our premium plan EduRev Infinity!

Content Category

Related Searches

Important questions

,

shortcuts and tricks

,

MCQs

,

pdf

,

Sample Paper

,

CBSE Test Paper - 01 CLASS - XII Chemistry (Surface chemistry) Answers Class 12 Notes | EduRev

,

Objective type Questions

,

Semester Notes

,

practice quizzes

,

Summary

,

CBSE Test Paper - 01 CLASS - XII Chemistry (Surface chemistry) Answers Class 12 Notes | EduRev

,

Previous Year Questions with Solutions

,

Exam

,

study material

,

video lectures

,

mock tests for examination

,

ppt

,

Viva Questions

,

past year papers

,

Extra Questions

,

Free

,

CBSE Test Paper - 01 CLASS - XII Chemistry (Surface chemistry) Answers Class 12 Notes | EduRev

;