question_answer

  Illustrate with examples : (a) Homogeneous and hetrogeneous catalysis.                                                                                                                  1 (b) Multi molecular and macromolecular colloids.                                                                                                              1 (c) Lyophilic and lyophobic sols.                                                                                                                                                 1

Answer:

  (a) Homogeneous catalyst: "When the reactant is in the same phase as the reactants and products, it is called homogeneous catalyst, e.g.,                                                                                                                                                                                 Heterogeneous catalyst: When the catalyst is in different phase than the reactant, it is called heterogeneous catalyst, e.g.,                                                                                                                                                   (b) Multi molecular colloids: The colloid in which colloidal particles are clusters or aggregates of smaller molecular, e.g., sulphur (So) - Molecule.                                                                                                                     Macromolecular colloids: There are the substances having big size molecules (called macromolecules) which on dissolution form solution in which the dispersed phase, e.g., colloidal solution of starch.                                                         (c) Lyophilic colloids: The colloidal solutions in which the particles of the dispersed phase have a great affinity for the dispersion medium, are called lyophilic colloids, e.g., glue, gelatin, starch, proteins, rubber etc.                                                         Lyophobic colloids: The colloidal solutions in which there is no affinity between particles of the dispersed phase and the dispersion medium are called lyophobic colloids, e.g., colloidal solution of gold, silver, etc.