MCQs on Surface Chemistry Part-2

Multiple Choice Questions part -2 for Surface Chemistry

Love to learn

These questions are useful for any Entrance exam which involves Science Questions

Question 1: Volume of gases CH₄, O₂, CO_2, and NH₃ adsorbed by charcoal at 288 K are in the order:

• CO₂> NH₃ > O₂ > CH₄
• NH₃ > CO₂ > O₂ > CH₄
• CH₄ > CO₂ > NH₃ > O₂
• CO₂ > CH₄ > NH₃ > O₂

Answer: The correct option is (b). Adsorption depends upon ability of adsorb which depends on critical temperature of gases.

Order of Critical temperature: NH₃ > CO₂ > O₂ > CH₄

 Question 2: If O₂ gas is absorbed on platinum then, it follows:  

• First-order reaction
• Second-order reaction
• 3^rd order reaction
• Zero-order reaction

Answer: The correct option is (d). The reaction which takes place on surface of heterogeneous catalyst proceeds by zero order reaction.

Question 3: Expression:  represents:

• Adsorption isotherm
• Freundlich isotherm
• Langmuir isotherm
• None of these

Answer: The correct option is (b). It is the equation of Freundlich Isotherm. It explains the behavior of adsorption accurately. In the equation x/m = k.P1/n (n > 1), 'k' and 'n' are constants that depend on the nature of the adsorbent and the gas at a particular temperature.

Question 4: Misty windows in winter are due to:

• Adsorption, ΔH= -ve
• Adsorption,ΔH= +ve

Answer: The correct option is (a). This is an exothermic reaction so,  for this. And H2O molecules in air get attracted towards glass window due to electrostatic force. So, they get adsorb on surface of glass window.

Question 5: Which of the following does not affect the extent of adsorption?

• Nature of gas
• Temperature
• pH of gas
• pressure of gas

Answer: The correct option is (c). The adsorption is depends upon nature of gas adsorbed, temperature, nature of adsorbent and pressure. It does not depend upon pH of gas.

Question 6: N₂ gas is at                low temperature and               at high temperature on iron surface:

• Physisorbed, Chemisorbed
• Chemisorbed, Chemisorbed
• Physisorbed, Physisorbed
• Chemisorbed, Physisorbed

Answer: The correct option is (a). At low temperature, N2 gas is physisorbed on iron surface and with increase in temperature physisorption is changed into chemisorptions. So, at high temperature, N2 gas is chemisorbed on iron surface.

Answer: The correct option is (d). Physical adsorption is a reversible process. In involves weak vander Waal forces of interaction between adsorbate and adsorbent.

Question 8: Milk and cream are examples of:

• Oil in water (o/w) emulsion and water in oil (w/o) emulsion
• water in oil (w/o) emulsion and Oil in water (o/w)
• Oil in water (o/w) and Oil in water (o/w)
• water in oil (w/o) emulsion and water in oil (w/o) emulsion

 Answer: The correct option is (a). In the case of milk, the dispersed phase= oil; dispersed medium=water; Hence it is Oil in water (o/w) emulsion. While in the case of cream, the dispersed phase= water; dispersed medium=oil; Hence it is water in oil (w/o) emulsion.

Question 9: Brownian motion is                  of particles: 

• Circular motion
• Straight-line motion
• Zigzag motion
• Vibratory motion

Answer: The correct option is (c). Brownian motion is a Zigzag motion of particles.

Question 10: Which of the following is the correct statement?

• Milk is an example of water in oil emulsion
• Brownian motion is responsible for the stability of the colloidal solution
• The formation of micelle takes place below Critical micelle concentration (CMC)
• All of the above

Answer: The correct option is (b). Brownian motion is responsible for stability of colloidal solution. Milk is an example of oil in water emulsion. The formation of micelle takes place above CMC.