Why does distilled water not conduct electricity, whereas rain water does?

Distilled water does not conduct electricity because it is essentially pure water, devoid of impurities and minerals. Pure water is a poor conductor of electricity because it lacks free ions, which are the charge carriers needed for electrical conductivity. In distilled water, there are very few ions present, so it does not provide a medium for electric current to flow.

On the other hand, rainwater conducts electricity because as rain falls through the atmosphere, it absorbs carbon dioxide and other gases, as well as dust and other impurities, which can provide ions when dissolved in water. For example, carbon dioxide reacts with water to form a weak solution of carbonic acid (H2CO3), which partially dissociates into hydrogen ions (H+) and bicarbonate ions (HCO3−), increasing the conductivity of water. Additionally, rainwater may pick up other dissolved salts and minerals as it comes into contact with surfaces on the ground, further enhancing its ability to conduct electricity.