Assertion (A) Colloidal solution show colligative properties.
Reason (R) Colloidal particles are large in size.
Assertion (A) Colloidal solutions do not show Brownian motion.
Reason (R) Brownian motion is responsible for stability of sols.
Assertion (A) Coagulation power of $\mathrm{Al}^{3+}$ is more than $\mathrm{Na}^{+}$.
Reason (R) Greater the valency of the flocculating ion added, greater is its power to cause precipitation (Hardy-Schulze rule).
Assertion (A) Detergents with low CMC are more economical to use.
Reason (R) Cleansing action of detergents involves the formation of micelles. These are formed when the concentration of detergents becomes equal to CMC.
What is the role of adsorption in heterogeneous catalysis?
Catalyst is used to increase rate of reaction. Heterogeneous catalyst is used to increase rate of reaction in which catalyst is not in phase with reactants and products.
Role of adsorption in heterogeneous catalysis are
(i) Diffusion of reactants to the surface of the catalyst.
(ii) Reactants are adsorbed on the catalyst surface.
(iii) Occurrence of chemical reaction at catalyst surface.
(iv) Desorption.
(v) Diffusion of reaction products away from the catalysts surface.
e.g.,
