Soaps are sodium & potassium salts of higher fatty acids.
Eg: C17H35COONa oil & Grease in dirt adhere firmly to clothing and is undisturbed by washing in tap water. Soap acts as an Emulsifying agent and brings the Greasy dirt into colloidal dispersion the hydrocarbon chain of soap molecule is soluble in oil or grease. It dissolves in grease and encapsulates. It form micelle. The anionic ends of chain protrude from droplets and interact with water molecules, preventing coalescence of droplets.