How is soap manafactured using sodium hydroxide?

Answer 1

Soap is manufactured in this way using a process called saponification of fats.

Fats fall into a category of compounds called esters, molecules formed from an alcohol and a carboxylic acid. In the case of a fat the alcohol is glycerin (glycerol) and the acid is a fatty acid.

Here is the generic, two-step equation for the saponification of an ester with a hydroxide (R represents the rest of each acid and ester).

OH- + RO2-OR --> RO2H + RO-

The ester is split into the corresponding acid and alkoxide ("salt" of an alcohol).

RO- + RO2H --> ROH + RO2-

Since ethoxides are highly basic they are quickly neutralized by the fatty acid. Resulting in the corresponding alcohol (glycerin) and fatter acid salt (the soap). The glycerin is then separated out.

Answer 2

To manufacture soap using sodium hydroxide in a process called saponification, oils or fats are mixed with sodium hydroxide in the presence of water. This chemical reaction breaks down the oils into fatty acids and glycerin, creating soap. Excess sodium hydroxide is neutralized before the soap can be used.