Question

Why does an aqueous solution of an acid conduct electricity?

Answer 1

Pure acids in the liquid state are exceedingly poor conductors of electricity. The fact that aqueous solutions of acids conduct electricity is definite evidence of the existence of ions in these solutions. Acids undergo dissociation in aqueous solution to form $H^{+}$ ions.

When electricity is passed through an aqueous solution of an acid, the $H^{+}$ ions reach the cathode and each $H^{+}$ ion picks up one electron from the cathode to form $H_{2}O$ gas. Because of this reaction, an aqueous solution of acid conducts electricity