salt of fatty acids (long-chain carboxylic acids), used for washing and cleaning
A bar of soap

Soap is a chemical compound resulting from the reaction of an alkali (commonly sodium or potassium hydroxide) with a fatty acid. Soaps are the metallic salts of long chain fatty acids. When mixed with water during bathing or washing, they help people and clothes get clean by lowering the chance of dirt and oil to get to the skin or fabric. Soaps are made from animal fats or vegetable oils. There are two basic steps in making soap. They are called Saponification and Salting-out of soap. Some people like to make their own soap.[1]

Soap cleans very well in soft water. It is not toxic to water life. It can be broken down by bacteria. However, it is slightly soluble in water, so it is not often used in washing machines. It does not work well in hard water. It cannot be used in strongly acidic solutions. Mild hand soaps are only basic enough to remove unwanted skin oils. For other forms of oil, dishwashing soap is strong enough to remove almost all forms of oil without damaging petroleum products such as plastics. It does not damage skin either.

Soap has been made in many ways. Humanity has used soap-like things for thousands of years. The earliest recorded evidence of the making of soap-like materials dates back to around 2800 BC in Ancient Babylon.[2] A recipe for soap having water, alkali and cassia oil was written on a Babylonian clay tablet around 2200 BC.[source?]

The Ebers papyrus (Egypt, 1550 BC) suggests that ancient Egyptians bathed commonly and had animal and vegetable oils with alkaline salts to make a soap-like substance. Egyptian documents say that a soap-like substance was used in the preparation of wool for weaving.


  1. "How to Make Your Own Soap". wikiHow. Retrieved 2018-12-28.
  2. Willcox, Michael (2000). "Soap". In Hilda Butler (ed.). Poucher's Perfumes, Cosmetics and Soaps (10th edition ed.). Dordrecht: Kluwer Academic Publishers. p. 453. The earliest recorded evidence of the production of soap-like materials dates back to around 2800 BCE in ancient Babylon.CS1 maint: extra text (link)

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