(25-10-2017, 11:13 AM)jaseela123 Wrote:

In chemistry, a soap is a salt of a fatty acid. Domestic uses for soaps include washing, bathing and other cleaning, in which soaps act as surfactants and emulsifying oils so they can be transported by water. In industry, they are also used in textile spinning and are important components of some lubricants. Metallic soaps are also included in the oil paints formulations of modern artists as a rheology modifier.

Cleaning soaps are obtained by treating vegetable or animal oils and fats with a strong base such as sodium hydroxide or potassium hydroxide in an aqueous solution. Fats and oils are composed of triglycerides; three molecules of fatty acids bind to a single molecule of glycerol. The alkaline solution, which is often called bleach (although the term "bleach soap" refers almost exclusively to soaps made with sodium hydroxide), induces saponification.

In this reaction, the triglyceride fats are first hydrolyzed into free fatty acids, and then the latter are combined with the alkali to form raw soap: an amalgam of various soap salts, excess fat or alkali, water and released glycerol ). Glycerin, a useful byproduct, may remain in the soap product as a softening agent or be isolated for other uses.

Soaps are key components of most lubricating greases, which are usually emulsions of calcium soap or lithium soap and mineral oil. Many other metallic soaps are also useful, including aluminum, sodium and mixtures thereof. Such soaps are also used as thickeners to increase the viscosity of oils. In ancient times, lubricating greases were made by adding lime to olive oil.