(a) Explain any two physical properties of ionic compounds giving reason.
(b) List any two metals found in free state in earth's crust. Where are they located in activity series ?
(c) Metals towards the top of the activity series can not be obtained from their compounds by reducing with carbon. Why?

Explanation

(a) Physical properties of ionic compounds:
(i) Ionic compounds are usually crystalline solids because their oppositely charged ions attract one another strongly and form a regular crystal structure.
(ii) Ionic compounds have high melting and high boiling points. The ionic compounds are made up of +ve and -ve ions. There is a strong force of attraction between the oppositely charged ions, so a lot of heat energy is required to break this force of attraction and melt of boil the ionic compounds.
(b) Gold and platinum metals are founds in free state in the earth's crust. These metals are located at the bottom in the activity series.
(c) Metals towards the top of the activity series are highly reactive. The oxides of highly reactive metals are very stable and can not be reduced by 'carbon' to obtain free metals because these metal have more affinity for oxygen than carbon.