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#### Surface Chemistry Model Question Paper

12th Standard EM

Reg.No. :
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Chemistry

Time : 02:00:00 Hrs
Total Marks : 50
8 x 1 = 8
1. For freudlich isotherm a graph of log $\frac{x}{m}$ is plotted against log P. The slope of the line and its y – axis intercept respectively corresponds to

(a)

$\frac{1}{n}$ ,K

(b)

log$\frac{1}{n}$ ,K

(c)

$\frac{1}{n}$ ,logK

(d)

log $\frac{1}{n}$ ,log K

2. Which of the following is incorrect for physisorption?

(a)

reversible

(b)

increases with increase in temperature

(c)

(d)

increases with increase in surface area

3. Hair cream is

(a)

gel

(b)

emulsion

(c)

solid sol

(d)

sol.

4. The most effective electrolyte for the coagulation of AS2S3Sol is

(a)

NaCl

(b)

Ba(NO3)2

(c)

K3[Fe(CN)6]

(d)

Al3+

5. The phenomenon observed when a beam of light is passed through a colloidal solution is

(a)

Cataphoresis

(b)

Electrophoresis

(c)

Coagulation

(d)

Tyndall effect

6. Collodion is a 4% solution of which one of the following compounds in alcohol – ether mixture?

(a)

Nitroglycerine

(b)

Cellulose acetate

(c)

Glycoldinitrate

(d)

Nitrocellulose

7. Adsorption of a gas on solid metal surface is spontaneous and exothermic, then

(a)

ΔH increases

(b)

ΔS increases

(c)

ΔG increases

(d)

ΔS decreases

8. If x is the amount of adsorb ate and m is the amount of adsorbent, which of the following relations is not related to adsorption process?

(a)

x/m=f(P) at constant T

(b)

x/m=f(T) at constant P

(c)

P = f(T) at constant x/m

(d)

x/m = PT

9. 6 x 2 = 12
10. Give two important characteristics of physiscorption

11. Differentiate physisorption and chemisorption

12. Heat of adsorption is greater for chemisorptions than physisorption. Why?

13. The mechanism of Fridel crafts reaction is given below
${ C }_{ 6 }{ H }_{ 5 }+{ { CH }_{ 3 }Cl\overset { anhydrous\\ \quad \quad \quad { Alcl }_{ 3 } }{ \longrightarrow } }{ C }_{ 6 }{ H }_{ 5 }{ CH }_{ 3 }+HCl$

14. Thermal decomposition of KClO in presence of MnO2 proceeds as follows.
Steps in the reaction 2KClO → 2KCl+3Ocan be given as

15. Formation of water due to the reaction of H2 and O2 in the presence of Cu can be given as

16. 5 x 3 = 15
17. What happens when a colloidal sol of Fe(OH)3 and AS2O3 are mixed?

18. What is the difference between a sol and a gel?

19. Addition of Alum purifies water. Why?

20. What are enzymes? Write a brief note on the mechanism of enzyme catalysis.

21. Describe some feature of catalysis by Zeolites.

22. 3 x 5 = 15
23. Give three uses of emulsions.

24. Explain any one method for coagulation

25. Describe adsorption theory of catalysis