Question

Give reasons for the following observations:
(i) Leather gets hardened after tanning.
(ii) Lyophilic sol is more stable than lyophobic sol.
(iii) It is necessary to remove CO when ammonia is prepared by Haber's process.

Answer 1

(i) Animal skin (hide) is colloidal in nature and has positively charged colloidal particles. When a hide is soaked in tanning, mutual coagulation takes places and as a result, leather get hardened.
(ii) The stability of lyophillic solution is depend on the result of two factors, the presence of a charge and the solvation of colloide particles. On the other hand, the stability of lyophobic solution is only because of the presence of a charge, Thus lyophillic solution is more stable than lyophobic solution due to the extensive solvation.
(iii) It is necessary to remove $CO$ when ammonia is prepared by Haber's process because in this process the $CO$ act as a poison and adversely afftects the activity of iron catalyst, used in the process