Question

what is saponification reaction? What is the nature of the reaction

Answer 1

Saponification is the name of the chemical reaction that produces soap. In the process, animal or vegetable fat is converted into soap (a fatty acid) and alcohol. The reaction requires a solution of an alkali (e.g., sodium hydroxide or potassium hydroxide) in water and also heat

Answer 2

Esters can be cleaved back into a carboxylic acid and an alcohol by reaction with water and a base. The reaction is called a saponification from the Latin sapo which means soap. The name comes from the fact that soap used to me made by the ester hydrolysis of fats.

Saphonification reaction mixture is basic  and reaction is exothermic.