Soap

The process of saponification, in which a fat (such as tallow) or an oil (such as coconut oil) is treated with an alkali, producing a product that has surfactant, emulsification, dispersant, and suspension properties. Soap is mildly alkaline, making it well suited for personal cleaning products.

The main drawback of soap is in laundry use where the reaction with hard water leaves a curd that is hard to rinse out of the fabric. Also, some soap is used up in combining with the minerals, leaving less for the cleaning.

Synthetic detergents have largely replaced soaps for laundry and home use with the exception of the familiar bar soap in the bath and shower.

Reference:

Soap and Detergent Association.