A Level Chemistry OCR Practice Exam

Which term best describes the breaking down of a compound by reaction with water?

1. Hydrogenation

2. Hydrolysis

3. Dehydration

4. Oxidation

The correct answer is: Hydrolysis

Hydrolysis is the term that accurately describes the process in which a compound is broken down by reaction with water. This chemical reaction involves the addition of water to the compound, resulting in the formation of simpler products. For example, when a salt dissolves in water, it can undergo hydrolysis to produce an acidic or basic solution depending on the nature of the ions involved. In contrast, hydrogenation refers to the addition of hydrogen to a compound, often used in converting unsaturated fats to saturated fats. Dehydration, on the other hand, involves the removal of water from a substance, typically resulting in the formation of a more concentrated product. Oxidation is a broader term that involves the loss of electrons or an increase in oxidation state, which may not involve water at all. Therefore, hydrolysis is the most appropriate term for the reaction involving the breakdown of compounds by water.