Question

In the preparation of a soap, a fatty acid containing less than eight carbon atoms is not used, because the soap obtained:

• A. Forms a colloidal solution with water
• B. Is insoluble in water
• C. Does not form an emulsion with grease
• D. Forms an emulsion with grease

Answer 1

The correct option is C Does not form an emulsion with grease

Soap has a tadpole like structure, because they possess a long carboxylic acid chain through which hydrocarbons and sodium-pottasium ions are attached. The ionic part dissolves in water whereas the non-ionic carbon chain dissolves in oil and forms an emulsion, but to form an emulsion, the non-ionic chain must have more than 8 carbon atoms.