Question map
Which one of the following substances is most likely to be used as soap?
Explanation
Soaps are chemically defined as the sodium or potassium salts of long-chain carboxylic acids (fatty acids) [2]. These molecules possess a long hydrocarbon chain that is hydrophobic and an ionic carboxylate end that is hydrophilic, allowing them to form micelles and emulsify oils for cleaning [2]. The substance CH3(CH2)12COONa is the chemical formula for sodium myristate, which is the sodium salt of myristic acid (a C14 saturated fatty acid). Sodium myristate is explicitly identified as a surfactant and a common ingredient used in the preparation of soaps and shaving creams. In contrast, option 1 is an ester (methyl myristate), option 2 is a long-chain alkane, and option 4 is an alkyl chloride, none of which possess the required ionic salt structure of a soap [1].
Sources
- [1] Science , class X (NCERT 2025 ed.) > Chapter 4: Carbon and its Compounds > CH COOH CH CH OH CH C C CH CH H O 3 3 2 3 2 3 2 Acid O (E - + - - - - - + thanoic acid) (Ethanol) (Ester) O > p. 73
- [2] Science , class X (NCERT 2025 ed.) > Chapter 4: Carbon and its Compounds > Activity 4.10 > p. 75