Which catalyst is commonly used in the esterification process?

The correct choice is concentrated sulfuric acid, which is commonly used as a catalyst in the esterification process. Esterification generally involves the reaction of an alcohol with a carboxylic acid to form an ester and water. This reaction can be slow and may not proceed efficiently under mild conditions.

Concentrated sulfuric acid serves as a strong acid catalyst that facilitates the reaction by protonating the carbonyl oxygen of the carboxylic acid. This increases the electrophilicity of the carbonyl carbon, making it more susceptible to attack by the alcohol. As a result, the reaction rate is enhanced, allowing the formation of the ester to occur more readily.

Moreover, sulfuric acid helps to shift the equilibrium of the reaction toward the product side by removing water that is produced during the esterification, thus driving the reaction forward. This dual role as both a catalyst and a dehydrating agent makes concentrated sulfuric acid particularly effective in this process.

In contrast, the other substances listed are not typically used as catalysts in esterification. For example, potassium permanganate is a strong oxidizing agent, sodium hydroxide is a strong base commonly used in saponification rather than esterification, and hydrochloric acid, while an acid, does