Soap is sodium or potassium salt of

Soap is chemically defined as the sodium or potassium salt of long-chain carboxylic acids, commonly known as fatty acids [1]. These salts are produced through the saponification process, where triglycerides (fats and oils) react with an alkali like sodium hydroxide or potassium hydroxide. The most common fatty acids involved in this reaction include stearic acid, palmitic acid, and oleic acid [2]. Specifically, tallow and lard—common soap-making fats—contain high concentrations of stearic and palmitic acids (saturated) and oleic acid (unsaturated). Sodium salts of these acids typically form hard soaps, while potassium salts result in softer soaps [1]. Since all three listed acids (stearic, oleic, and palmitic) are primary components used to form these metallic salts in soap production, the correct answer is 'All of the above'.

Sources

1. [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. [2] Science , class X (NCERT 2025 ed.) > Chapter 4: Carbon and its Compounds > Activity 4.10 > p. 75