Question

Why does distilled water not conduct electricity where as rain water does?

Answer 1

Distilled water does not contain any ionic compounds like acids ,bases or salts to produce ions.
Hence distilled water does not conduct electricity .
On the other hand rain water while falling to earth through the atmosphere dissolves some acidic gases like CO2,SO2 and N2O and forms acids such as H2CO3,H2SO3 and HNO3.
These acids produce ions.Due to presence of ions rain water conducts electricity .

Answer 2

Rain water dissolves gases present in the atmosphere like CO2 , SO2 , NO2 to form acids such as carbonic acid , sulphuric acid , nitric acid . These acids are present in very less amount but since they dissociate easily into ions and thus rain water conducts electricity. On the other hand ,distilled water does not contain any such ions which can conduct electricity.