MCQs – Surface Chemistry – Part-3

MCQs – Surface Chemistry – Part-3 Prepared by experts for any entrance exam.
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Question 21: Match the following:

Column I Column II

Physisorption (p) Multilayer adsorption
Chemisorption (q) Plot of ‘t’ versus ‘p’ for adsorption
Desorption (r) Strong covalent forces
Adsorption isotherm (s) Occurs at high temperature

1-p, 2-r, 3-q, 4-s
1-p, 2-r, 3-s, 4-q
1-p, 2-q, 3-r, 4-s
1-q, 2-r, 3-p, 4-s

Answer: The correct option is (b). Physisorption is a type of multilayer adsorption, Chemisorption involves strong covalent bonds, Desorption occurs at high temperature and Adsorption isotherm is a graph of t versus p for adsorption.

Question 22: Adding 1 mL solution of 10% NaCl to 10 mL of red gold solution in presence of 0.47 g of starch, the coagulation is just avoided. The gold number of starch is. Choose one option of the following:

Answer: The correct option is (b) Gold number of starch is the amount of starch in mg added to 10 mL standard gold sol which avoids the coagulation of when 1mL of 10% NaCl solution is added.

0.47g=470mg. So, gold number=470

Question 23: The graph between log x/m and log p is a straight line at 45⁰ with an intercept of 0.4771 on the y-axis. What is the amount on the gas adsorbed in gm per gm of adsorbent when pressure is 3 atm?

Answer: By using graph;

Question-23

Explanation

x/m=kP^(1/n)

Taking log both sides;
log x/m=log kP^(1/n)
log x/m=1/n log kP
Using line intercept equations, 
y=mx+c; Where, m is the slope. Here, K=3 (log K=0.4771)
1/n =tan 45=1
n=1 x/m=kP^(1/n)=3*3 =9

Question 24: Out of the following – Which represents associated colloidal particles?

Proteins
Starch
Gold sol
Soaps

Answer: The correct option is (d).

Question 25: Out of the following – Which of the following is an example of macromolecular sol?

Synthetic detergent
Proteins
Sulphur sol
Gold sol

Answer: The correct option is (b).

Question 26: Which of the following is an incorrect statement?

Zeolites are good shape-selective catalysts.
Zeolites are used as a catalyst for polymerization of ethene
Zeolites have a honey-comb like structure
ZSM-5 converts alcohol directly into gasoline.

Answer: The correct option is (b).

Question 27: Which statement is/are correct about emulsions?

Demulsification can take place by chemical methods only
A small amount of water cannot be mixed in water in oil emulsion
Sodium oleate is used to prepare water in oil emulsion
Both (a) and (c)

Answer: The correct option is (b). A small amount of water can destabilize the water in oil emulsion

Question 28: Gold number of starch = 15. To avoid coagulation of 100 mL of gold sol adding 1 mL of 10% NaCl solution how much starch is required

15 g
5 mg
15 mg
150 mg

Answer: The correct option is (d). We know, Gold number of starch is the amount of starch in mg added to 10 mL standard gold sol which prevents coagulation of gold on adding 1 mL of 10% NaCl solution. So, for 100 mL of gold sol amount of starch to be added.

Question 29: A oil in water emulsion has

High electrical conductivity
Easy dilution with oil soluble
No response to oil-soluble dye test
Both (a) and (b)

Answer: The correct option is (a). Oil in water emulsion has high electrical conductivity.

Question 30: Match the following:

Column I Column II

Fog (p) Gel
Gemstones (q) Emulsion
Cheese (r) Aerosol
Milk (s) Solid sol

—————————–

1-r, 2-p, 3-s, 4-q
1-r, 2-s, 3-p, 4-q
1-q, 2-s, 3-p, 4-r
1-r, 2-s, 3-q, 4-p

Answer: The correct option is (b). Fog is an aerosol, Gemstones are an example of a solid sol, cheese is an example of gel and milk is an example of an emulsion.