How does the soap clean?

If soap is made from oils and grease, how is it able to clean greasy surfaces? It's a curious question, since the basic composition of soaps is precisely animal fats. and vegetable oils, all insoluble in water, hence why water alone does not clean these compounds.
A great discovery revolutionized cleaning, through which it is possible to clean accumulated dirt. Everything is very simple: the mixture of oils (esters) with alkaline solutions (sodium or potassium hydroxide) gave rise to a product that dissolves in water and removes fat. We're talking about soap, follow the equation that made its production possible:
Oil + base → soap + glycerol
Returning to the previous question, if oils are insoluble in water, how can they be removed using soap and water? Thanks to the soap's polar and non-polar character. Below is a demonstration of how the interaction between soap, water and oil works.

Note that the soap molecule has a polar part and a non-polar part. The nonpolar chain formed by hydrocarbons (−

CH₂) is attracted to oils (non-polar) and the polar tip (containing ions) interacts with water. We then say that the molecule COONa it is polar and hydrophilic (reacts with water) and the hydrocarbon chain is hydrophobic (has aversion to water). This force of attraction is based on the rule: “like dissolves like”.
Thus it is possible to form an emulsion (mixture) characterized by foam. It is from this interaction between the components of the soap that it is possible to clean surfaces full of grease.

Do not stop now... There's more after the advertising ;)

By Líria Alves
Graduated in Chemistry
Brazil School Team

See more!
Soap or washing, which came first?
Turning used cooking oil into soap.

Chemistry Curiosities - Chemistry - Brazil School

Would you like to reference this text in a school or academic work? Look:

SOUZA, Líria Alves de. "How does soap clean?"; Brazil School. Available in: https://brasilescola.uol.com.br/quimica/como-sabao-limpa.htm. Accessed on June 28, 2021.