After the hydrolysis of ester the change in concentration of acid at different intervals is calculated by:

Explanation

After the hydrolysis of an ester, the change in concentration of acid at different intervals can be calculated by titration. The hydrolysis of an ester produces a carboxylic acid and an alcohol. To determine the concentration of the acid produced, a sample of the reaction mixture can be taken at different intervals and titrated against a standardized solution of a strong base, such as sodium hydroxide. The volume of the base required to neutralize the acid in the sample can be used to calculate the concentration of the acid at that particular interval. Thus, option B is correct.