Electrolytes and Nonelectrolytes for AP Chemistry

By — McGraw-Hill Professional
Updated on Feb 9, 2011

Practice problems for these concepts can be found at:

An electrolyte is a substance that, when dissolved in a solvent or melted conducts an electrical current. A nonelectrolyte does not conduct a current when dissolved. The conduction of the electrical current is usually determined using a light bulb connected to a power source and two electrodes. The electrodes are placed in the aqueous solution or melt, and if a conducting medium is present, such as ions, the light bulb will light, indicating the substance is an electrolyte.

The ions that conduct the electrical current can result from a couple of sources. They may result from the dissociation of an ionically bonded substance (a salt). If sodium chloride (NaCl) is dissolved in water, it dissociates into the sodium cation (Na+) and the chloride anion (Cl). But certain covalently bonded substances may also produce ions if dissolved in water, a process called ionization. For example, acids, both inorganic and organic, will produce ions when dissolved in water. Some acids, such as hydrochloric acid (HCl), will essentially completely ionize. Others, such as acetic acid (CH3COOH), will only partially ionize. They establish an equilibrium with the ions and the unionized species (see Chapter 13 for more on chemical equilibrium).

Species such as HCl that completely ionize in water are called strong electrolytes, and those that only partially ionize are called weak electrolytes. Most soluble salts also fall into the strong electrolyte category.

Practice problems for these concepts can be found at:

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