Surface Chemistry MCQs

Surface chemistry focuses on the study of phenomena occurring at the interface between two bulk phases. Adsorption refers to the process where molecules of a substance adhere to the surface of a liquid or solid, leading to an increased concentration of these molecules at the surface. The substance that gets adsorbed is known as the adsorbate, while the surface on which it adheres is called the adsorbent. Desorption is the process of removing adsorbed substances from the surface. Occlusion specifically refers to the adsorption of gases onto the surface of a solid.

Which one of the following is an example of adsorption?

(a) ammonia in contact with water
(b) anhydrous CaCl2 with water
(c) silica gel in contact with water vapours
(d) all of these

The process of separating a crystalloid from a colloid by filtration is called:

(a) emulsification
(b) dialysis
(c) coagulation
(d) peptization

The volume of gases H2, CH4, CO2, and NH3 adsorbed by 1 gm charcoal at 293 K can be given in the order:

(a) CH4 > CO2 > NH3 > H2
(b) CO2 > NH3 > H2 > CH4
(c) NH3 > CO2 > H2 > CH4
(d) NH3 > CO2 > CH4 > H2

An emulsifier is a substance which:

(a) stabilizes the emulsion
(b) coagulates the emulsion
(c) retards the dispersion of liquid in liquid
(d) causes homogenization of emulsion

At 15°C, which gas will be adsorbed the most by charcoal?

(a) H2
(b) CH4
(c) CO2
(d) NH3

Which of the following kinds of catalysis can be explained by the adsorption theory?

(a) enzyme catalysis
(b) homogeneous catalysis
(c) acid-base catalysis
(d) heterogeneous catalysis

The movement of colloidal particles towards the oppositely charged electrodes on passing electric current is known as:

(a) Tyndall effect
(b) cataphoresis
(c) Brownian movement
(d) none of these

If the dispersed phase is a liquid and the dispersion medium is solid, the colloid is known as:

(a) foam
(b) sol
(c) emulsion
(d) gel

Homogeneous catalysis means:

(a) reactants and products have to be at the same level
(b) catalyst and reactants must be in the same phase
(c) the reaction mixture must be formed homogeneously during
(d) the reaction mixture distribution must be homogeneous

Which of the following colloids are solvent-hating?

(a) lyophilic
(b) lyophobic
(c) hydrophilic
(d) none of these