Strong acids and strong bases dissociate completely into ions when in solution. The presence of free ions to move under an electric current makes them strong electrolytes.
An electrolyte is a liquid that can conduct electricity due to the presence of free ions in solution. Most ionic compounds do not conduct electricity in a solid state, since the ions are tightly bound by electrostatic forces, but when dissolved in water, they can form electrolytes.
Electrolytes can be classified into two types depending on the degree of dissociation of the solute particles: strong electrolytes and weak electrolytes. Strong electrolytes include all strong acids, strong bases and salts. In order to be a strong electrolyte, the substance in question must be an ionic compound and must also be able to dissociate completely into its constituent ions when in solution. Weak electrolytes consists of solutes that do not dissociate completely in solution and are present as a mixture of ions and whole molecules.
Strong acids are ionic and tend to release hydrogen ions when in solution. Hydrochloric acid, sulfuric acid, nitric acid, hydroiodic acid, hydrobromic acid and perchloric acid are considered to be strong acids because they dissociate completely into ions when in solution. For example, hydrochloric acid dissociates and forms H+ and Cl- in solution, which can then move around under the influence of electricity.