Electrolyte and Nonelectrolyte Solutions

Water can dissolve many substances because of its chemical composition. Although its overall electrical charge is neutral, a water molecule has a partial negative charge at its oxygen end, and a partial positive charge at each of its hydrogen ends. This makes water a polar solvent.

When an ionic solute, such as a solid ionic compound, is added to water, the water molecules interact with the ions of the solute.

If the strong solute–solvent attractive forces overcome the solute–solute interactions holding the compound together, the solute ions are pulled apart.

The polar water molecules surround, or ‘hydrate’, the ions as they are separated. The hydrated ions are then dispersed uniformly throughout the solution.

When an electric potential is applied to an ionic solution, the ions become charge carriers that move towards the oppositely charged electrodes. This creates a current in the solution; in other words, it conducts electricity.

Substances that produce electrically conductive solutions when dissolved in polar solvents are called electrolytes. Sodium chloride is one such example.

However, when a molecular compound such as sucrose dissolves in water, its molecules remain intact as