PGT Chemistry Study Material – Surface Chemistry Mock Test

Introduction

Surface Chemistry is an essential topic in the PGT Chemistry exam, covering adsorption, catalysis, and colloidal systems. This 30-question mock test will help you assess your knowledge and enhance your preparation.

Mock Test: Surface Chemistry (30 Questions)

Instructions:

• Each question carries 1 mark.
• No negative marking for incorrect answers.
• Answer key provided at the end.

1. Adsorption is the process where a substance:

(a) Diffuses into another substance
(b) Accumulates on the surface of another substance
(c) Forms a solid solution
(d) Remains unaffected

2. Which of the following is an example of physisorption?

(a) Hydrogen on finely divided nickel
(b) Oxygen on a metal surface
(c) Nitrogen on silica gel
(d) Ammonia on activated charcoal

3. Chemisorption:

(a) Is irreversible
(b) Increases with temperature
(c) Is highly specific
(d) All of the above

4. The extent of adsorption of gas on a solid surface increases with:

(a) Increase in temperature
(b) Increase in surface area of the adsorbent
(c) Increase in the size of the gas molecule
(d) Decrease in pressure

5. The adsorption of gases on a solid is generally:

(a) Endothermic
(b) Exothermic
(c) Neither endothermic nor exothermic
(d) Constant for all gases

6. Freundlich adsorption isotherm is valid for:

(a) Multilayer adsorption
(b) Monolayer adsorption
(c) Both monolayer and multilayer adsorption
(d) Chemical adsorption

7. Which of the following is an example of a lyophilic colloid?

(a) Gum
(b) Gold sol
(c) Ferric hydroxide sol
(d) Sulfur sol

8. Which method is used to protect a colloid?

(a) Electrophoresis
(b) Addition of electrolytes
(c) Peptization
(d) Addition of a lyophilic colloid

9. The coagulation of colloidal particles by an electrolyte is called:

(a) Peptization
(b) Dialysis
(c) Electrophoresis
(d) Flocculation

10. Gold number is:

(a) The minimum amount of an electrolyte required to coagulate a colloid
(b) The minimum amount of a protective colloid required to prevent coagulation of gold sol
(c) The temperature at which a colloid coagulates
(d) The concentration of dispersed phase in a colloid

11. A characteristic of lyophobic colloids is:

(a) Easily coagulated
(b) Thermodynamically stable
(c) Strong interaction between particles
(d) Irreversible formation

12. Tyndall effect is observed in:

(a) True solution
(b) Colloidal solution
(c) Electrolyte
(d) Suspension

13. Removing electrolytes from a colloidal solution by dialysis is:

(a) Peptization
(b) Coagulation
(c) Purification
(d) Tyndall effect

14. Brownian movement in colloidal particles:

(a) Decreases with an increase in particle size
(b) Increases with an increase in temperature
(c) Is independent of particle size
(d) Both (a) and (b)

15. The electrokinetic potential in colloidal solutions is called:

(a) Zeta potential
(b) Dipole moment
(c) Electrode potential
(d) Polarizability

16. Which colloid is used in medicine for detoxification?

(a) Silver sol
(b) Gold sol
(c) Starch sol
(d) Sulfur sol

17. Critical micelle concentration (CMC) is associated with:

(a) Emulsions
(b) Micelle formation in surfactants
(c) Gel formation
(d) None of the above

18. Colloidal particles can be removed by:

(a) Tyndall effect
(b) Ultrafiltration
(c) Electrophoresis
(d) Precipitation

19. In lyophilic colloids, the colloidal particles are:

(a) Solvent-repelling
(b) Solvent-attracting
(c) Electrolyte-repelling
(d) Electrolyte-attracting

20. Emulsion is used for:

(a) Solid in liquid colloid
(b) Liquid in liquid colloid
(c) Gas in liquid colloid
(d) Gas in solid colloid

21. A catalyst increases reaction rate by:

(a) Increasing activation energy
(b) Decreasing activation energy
(c) Increasing enthalpy change
(d) None of the above

22. An example of heterogeneous catalysis is:

(a) Iron in the Haber process
(b) Sulfuric acid in esterification
(c) Platinum in the Contact process
(d) Both (a) and (c)

23. Colloidal solution of gold appears:

(a) Red
(b) Blue
(c) Yellow
(d) Violet

24. Colloids can be prepared using:

(a) Peptization
(b) Condensation
(c) Bredig’s arc method
(d) All of the above

25. In Freundlich isotherm, the value of n:

(a) Is always less than 1
(b) Is always greater than 1
(c) Lies between 1 and 10
(d) Is always greater than 10

26. To increase colloid stability, we use:

(a) Electrolytes
(b) Increasing particle size
(c) Decreasing particle size
(d) Addition of protective colloids

27. Langmuir adsorption isotherm applies to:

(a) Multilayer adsorption
(b) Monolayer adsorption
(c) Both monolayer and multilayer adsorption
(d) Chemisorption only

28. Hardy-Schulze rule is related to:

(a) Coagulation of colloids
(b) Preparation of colloids
(c) Stability of colloids
(d) Purification of colloids

29. Which method separates colloidal particles?

(a) Centrifugation
(b) Filtration
(c) Dialysis
(d) Sedimentation

30. Self-dispersion in lyophilic colloids is called:

(a) Coagulation
(b) Peptization
(c) Spontaneous dispersion
(d) Brownian motion

Answer Key:

1 (b), 2 (c), 3 (d), 4 (b), 5 (b), 6 (c), 7 (a), 8 (d), 9 (d), 10 (b), 11 (a), 12 (b), 13 (c), 14 (d), 15 (a), 16 (a), 17 (b), 18 (b), 19 (b), 20 (b), 21 (b), 22 (d), 23 (a), 24 (d), 25 (c), 26 (d), 27 (b), 28 (a), 29 (c), 30 (c).

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