Which term describes the chemical process in which a substance reacts with water to form ions?

• A. Buffer Solution
• B. Titration
• C. Hydrolysis reaction
• D. pOH

Answer: (C)

Hydrolysis is the process where a substance reacts with water to yield ions or new ionic species. In water, the substance interacts with H2O to produce hydronium or hydroxide ions (or other ions) that change the solution chemistry. This is why salts derived from weak acids or weak bases often produce acidic or basic solutions through hydrolysis, and why compounds like metal oxides or esters can form hydroxides or acids upon reaction with water. For example, a salt of a weak base hydrolyzes to give OH− in solution, while a salt of a strong acid and a weak base tends to produce H3O+ and an acidic solution. By contrast, a buffer is a system that resists pH changes rather than describing a specific reaction with water to form ions, a titration is a method to determine concentration, and pOH is simply a measure of hydroxide ion concentration, not a process.