Soap | Synthetic detergent |
They are sodium and potassium salts of higher fatty acids like steric acid, palmitic acid, lauric acid, linoleic acid. | Synthetic detergents are sodium salts of alkyl hydrogen sulphate of alcohol or alkyl benzene sulphonates |
Soaps are completely biodegradable | Synthetic detergents are not completely biodegradable. |
Soaps cannot be used in hard water. | Synthetic detergents can be used in hard water. |