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Q58 (CISF/2025) Science & Technology › Basic Science (Physics, Chemistry, Biology)

Which of the following statements about detergents is/are correct ?
1. Detergents are generally sodium salts of long-chain carboxylic acids.
2. Detergents are generally calcium salts of long-chain carboxylic acids.
Select the answer using the code given below :

Explanation

Neither statement is correct. According to chemistry standards (and NCERT), soaps are sodium or potassium salts of long-chain carboxylic acids (fatty acids) such as stearic or palmitic acid. Synthetic detergents, however, are generally sodium salts of long-chain benzene sulphonic acids or sodium salts of long-chain alkyl hydrogen sulphates. Therefore, Statement 1 is incorrect as it describes soap, not detergents.

Statement 2 is also incorrect because calcium and magnesium salts of long-chain carboxylic acids are insoluble in water. These salts form an insoluble precipitate known as "scum" when soap is used in hard water, which hinders cleaning. Detergents are effective in hard water specifically because their calcium and magnesium salts are water-soluble and do not form scum.

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SIMILAR QUESTIONS

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