What process involves measuring the amount of a solution of known concentration required to react with a solution of unknown concentration?

The process that involves measuring the amount of a solution of known concentration required to react with a solution of unknown concentration is titration. Titration is a quantitative analytical method used to determine the concentration of a solute in a solution. In this method, a titrant (the solution of known concentration) is added to a titrand (the solution of unknown concentration) until the reaction reaches a specific endpoint, which is often indicated by a color change or an instrument measurement.

The endpoint signifies that stoichiometric amounts of both reactants have reacted, allowing for the calculation of the unknown concentration based on the volume of titrant used. This technique is particularly common in acid-base chemistry, where an acid solution is titrated with a base (or vice versa), but it can also be applied to redox reactions and other types of chemical reactions.

Other processes listed, such as autoprotolysis, neutralization, and hydrolysis, do not specifically focus on the direct measurement of concentration through volumetric addition and endpoint determination to quantify an unknown solution. Neutralization, for instance, can be a part of titration but does not describe the entire process.