Xiomara Nieves

You're absolutely right to identify this as an ester hydrolysis under basic conditions. In base-catalyzed ester hydrolysis (also known as saponification), water is not only useful as a solvent, but it is essential as the nucleophile that participates in the mechanism. The hydroxide ion (OH⁻) from NaOH attacks the carbonyl carbon of the ester, forming a tetrahedral intermediate, which then eliminates the alkoxide group (e.g., CH₃O⁻) and yields the carboxylate anion. The presence of H₂O in the reaction mixture helps maintain the ionic environment and allows for proton transfers, especially in the final neutralization step with H₃O⁺, as shown in your reaction scheme. So yes, water is absolutely necessary here—not just as solvent, but as a participant in the reaction mechanism. You're absolutely right to identify this as an ester hydrolysis under basic conditions. In base-catalyzed ester hydrolysis (also known as saponification), water is not only useful as a solvent, but it is essential as the nucleophile that participates in the mechanism. The hydroxide ion (OH⁻) from NaOH attacks the carbonyl carbon of the ester, forming a tetrahedral intermediate, which then eliminates the alkoxide group (e.g., CH₃O⁻) and yields the carboxylate anion. The presence of H₂O in the reaction mixture helps maintain the ionic environment and allows for proton transfers, especially in the final neutralization step with H₃O⁺, as shown in your reaction scheme. So yes, water is absolutely necessary here—not just as solvent, but as a participant in the reaction mechanism.