Soaps are esters of Fatty acids
Soaps are commonly used for cleaning purposes and are made from the reaction between a fatty acid and an alkali. Fatty acids are long-chain carboxylic acids that are typically derived from natural sources such as vegetable oils or animal fats. These fatty acids are esterified with an alkali, such as sodium hydroxide (NaOH) or potassium hydroxide (KOH), to form soap molecules.

Fatty acids as the precursor of soaps
Fatty acids contain a carboxyl group (COOH) at one end and a long hydrocarbon chain at the other end. The carboxyl group is acidic in nature and can react with an alkali to form a salt, which is the soap. The reaction between a fatty acid and an alkali is called saponification.

Saponification reaction
During the saponification reaction, the carboxyl group of the fatty acid reacts with the alkali, resulting in the formation of a carboxylate ion (RCOO-) and an alcohol molecule (R-OH). The carboxylate ion then combines with the alkali metal cation (e.g., Na+) to form the salt, which is the soap.

Fatty acids in soap structure
The soap molecules consist of a hydrophilic (water-loving) head and a hydrophobic (water-repelling) tail. The hydrophilic head is the carboxylate group, which is negatively charged and attracted to water molecules. The hydrophobic tail is the long hydrocarbon chain, which is nonpolar and repels water.

Working mechanism of soap
When soap is used for cleaning, the hydrophobic tails of soap molecules interact with grease, oil, or dirt particles, while the hydrophilic heads remain attracted to water. This allows the soap to surround and encapsulate the grease or dirt particles, forming structures called micelles. These micelles can then be rinsed away with water, carrying the dirt with them.

Conclusion
In conclusion, soaps are esters of fatty acids. Fatty acids are carboxylic acids derived from natural sources, and they undergo a saponification reaction with an alkali to form soap molecules. The soap structure consists of a hydrophilic head (carboxylate group) and a hydrophobic tail (hydrocarbon chain), allowing it to effectively clean by interacting with both water and grease or dirt particles.