Give reasons for the following observations : (3 marks)
(i) Leather gets hardened after tanning.
(ii) Lyophilic sol is more stable than lyophobic sol.
(iii) It is necessary to remove when ammonia is prepared by Haber’s process.
(i) mutual coagulation (1 marks)
(ii) strong interaction between dispersed phase and dispersion medium or solvated layer (1 marks)
(iii) acts as a poison for catalyst or iron (1 marks)