In the preparation of a soap, the fatty acid containing less than eight carbon atoms is not used, because the soap obtained:
Correct answer: C. Does not form an emulsion with the grease
- A. Forms a colloidal solution with water
- B. Is soluble in water
- C. Does not form an emulsion with the grease
- D. Forms an emulsion with the grease
Explanation
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.
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