Q.7: Why does distilled water not conduct electricity, whereas rain water does?
Distilled water which is a pure form of water, is neither acidic nor basic in nature. So distilled water does not dissociate into ions. Since, conduction of electricity requires free ions so, distilled water does not conduct electricity.
Rain water being an impure form of water, contains many ionic species. These ions are responsible for electrical conductivity of rain water.