What is the side product of the soap industry? Give reactions showing soap formation.

(N/A) The side product of the soap industry is glycerol.
Soaps are sodium or potassium salts of long-chain fatty acids such as stearic acid,oleic acid,and palmitic acid.
Soap is formed by heating fat (glyceryl ester of fatty acid) with aqueous sodium hydroxide. This reaction is known as saponification.
The chemical reaction is:
$CH_2OCOC_{17}H_{35}-CHOCOC_{17}H_{35}-CH_2OCOC_{17}H_{35} + 3NaOH \rightarrow 3C_{17}H_{35}COONa + CH_2OH-CHOH-CH_2OH$
In this reaction,the esters of fatty acids are hydrolysed,and the soap obtained remains in colloidal form. It is precipitated from the solution by adding $NaCl$.