Question

The correct statement(s) about surface properties is(are)

• A. Adsorption is accompanied by decrease in enthalpy and decrease in entropy of the system
• B. The critical temperatures of ethane and nitrogen are $563\, K$ and $126\, K$, 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

Answer 1

Answer: (A), (B)

In adsorption process both $\Delta H \& \Delta S$ is $- ve$. Higher the critical temperature of a gas higher the extent of adsorption.
Cloud is not an emulsion. Brownian motion depends on the size of the particles.