Give reason:
(i) Potash alum is used in clarification of water.
(ii) A solid catalyst is very efficient in the finally divided state.
(iii) Lyophilic sols are more stable than lyophobic sols.

Give reason '' Potash alum is used in the clarification of water

Give reason : A solid catalyst is very efficient in the finely dvided state.

Give reason : Lyophillic sols are more stable than lyophobic sols.

Give reason: (i) Methyl amine is soluble in water but not in aniline. (ii) Methyl amine is more basic than ammonia.

Give reasons for the following : (i) Ionic compounds have high melting point and boiling point. (ii) Ionic compounds conduct electricity in molten state. (iii) Ionic compounds are solids at room temperature and are somewhat hard.

Give reasons: (i) "Alloys of iron are more useful when compared to pure iron." (ii) Copper loses its brown layer gradually when exposed to air. (iii) Aluminium oxide is called amphoteric oxide.

State reason for the following : (i) Non-metals cannot displace hydrogen from the acids. (ii) Hydrogen is not a metal, yet it is placed in the activity series of metals. (iii) Aluminium is more reactive than iron, yet its corrosion is less than that of iron.