WJEC Chemistry Practice Exam 2025 - Free Chemistry Practice Questions and Study Guide

An electrolyte is defined as a substance that dissociates into ions when dissolved in water, allowing the solution to conduct electricity. This property is crucial in various chemical and biological processes, such as nerve signal transmission and muscle contraction. When an electrolyte dissolves, it separates into positive and negative ions, which are free to move in the solution. This movement of ions is what enables the solution to conduct an electric current.

The presence of these charged particles is essential in many applications, including batteries and electrolysis. In contrast, a non-conducting solid does not have free-moving charged particles, and a stable compound at all temperatures would not accurately describe the behavior of electrolytes, which can vary with temperature changes. A liquid with no ions would also lack the ability to conduct electricity, further distinguishing it from the definition of an electrolyte.