A Level Chemistry OCR Practice Exam

Hydrolysis refers specifically to a chemical reaction in which water is used to break down a compound. This can involve the splitting of a larger molecule into smaller units in the presence of water, leading to the formation of various products. Hydrolysis reactions are common in many biological and chemical processes, such as the breakdown of polysaccharides into monosaccharides or the conversion of esters into acids and alcohols. The other options, while involving reactions with other substances, do not encapsulate the core definition of hydrolysis. A reaction with alcohol, acids, or bases may involve alternative mechanisms or processes, but hydrolysis distinctly requires water as a reactant in the breakdown or transformation of substances. Thus, the definition clearly aligns with the involvement of water in the reaction.