QJEEAdv17Ch40a6: JEE Advanced 2017 Chemistry - Class 12 JEEAdv17Ch40a6 Solution: The correct statement(s) about surface properties is (are)
Multiple Choice Options
- A Adsorption is accompanied by decrease in ethalpy and decrease in entropy of the system
- B The critical temperatures of ethane and nitrogen are and respectively. The adsorption of ethane will be more than that of nitrogen on same amount of activated charcoal at a given temperature
- C Cloud is an emulsion type of colloid in which liquid is dispersed phase and gas is dispersion medium
- D Brownian motion of colloidal particles does not depend on the size of the particles but depends on viscosity of the solution
Step-by-Step Verified Solution
Option (A) : Correct. Adsorption is a surface phenomenon in which the concentration of the adsorbate increases only on the surface. It is always accompanied by a decrease in the entropy ( S). Since adsorption is an exothermic process, the enthalpy change ( H) of the system is also negative.
Option (B) : Correct. Easily liquefiable gases, that is, gases with high critical temperatures, are more readily adsorbed because van der Waals forces are stronger near the critical temperature. Thus, the adsorption of ethane will be more than that of nitrogen.
Option (C) : Cloud is an aerosol in which liquid is dispersed phase and gas is dispersion medium. Whereas, emulsion is liquid in liquid colloidal system.
Option (D) : Incorrect. Brownian movement varies with the size of the particles and viscosity of the solution. Smaller particles with lower viscosity show faster movement.