International General Certificate of Secondary Education (IGCSE) Chemistry Practice Exam

Electrolysis is the process in which electrical energy is used to cause a chemical change, typically the breakdown of a substance into its component parts, which is described accurately in the correct answer. In electrolysis, an electrical current is passed through an electrolyte, which is a liquid or gel that contains ions and can conduct electricity. This current drives a non-spontaneous chemical reaction, leading to the separation of elements or compounds.

For instance, during the electrolysis of water, an electric current splits the water molecules into hydrogen and oxygen gas. This demonstrates the core principle of electrolysis—the use of electricity to induce a chemical change, often resulting in the decomposition of the original substance. The process has significant applications, including in the extraction of metals from ores and electroplating.

The other options do not accurately describe the process of electrolysis. The transfer of heat through a liquid pertains to thermal conductivity rather than electrolysis. The conversion of electrical energy into kinetic energy relates to mechanical work, not necessarily involving a chemical change. Lastly, while electricity can influence the formation of chemical bonds, electrolysis specifically involves breaking down substances rather than forming new bonds through electric processes.