Question

Neither dry soil nor pure water conducts electricity but wet soil will conduct electricity. Explain why this happens?

Answer 1

Conduction of electricity takes place when there are ions in the medium. The pure water has no ions to conduct electricity. When it has dissolved ions it will conduct electricity. In the case of dry soil it is very resistive to electricity. But when wet it has ions in water molecules among the soil particles. Then the soil becomes a conductor of electricity.

Answer 2

In dry soil there is electrolyte (substance that produces an electrically when dissolved in a polar solvent), but that electrolyte is not dissolved, to produce electricity free ions are needed. In pure water there is a very small amount of ions (H⁺ and OH⁻). In wet soil dissolved electrolyte separates into cations and anions, movement of anions and cations in opposite directions make current.