(a) Ionic compounds are made up of oppositely charged ions which are held together by strong electrostatic force of attraction. Due to this reason, they are hard solids. When large pressure is applied, they tend to break into pieces.

(b) Conduction of electricity is achieved by the movement of charged particles. In the molten state or in their aqueous solution form, ionic compounds contain ions which can move throughout the solution/molten solid, which helps in conducting electricity.