GS PrelimsScience and TechnologyGeneral Science2003

Consider the following statements The purpose of adding sodium sulphate and sodium silicate to the detergent in a washing powder is 1. 1. To keep the washing powder dry 2. 2. To maintain the alkalinity of the powder Which of these statements is/are correct?

A

Only 1

B

Only 2

C

Both 1 and 2

D

Neither 1 nor 2

Correct Answer: Option C

Explanation

1 Detergents used in washing powder contain various additives besides the active surfactant. 2 Statement 1 is correct. Sodium sulphate is often added as a filler. It is hygroscopic (absorbs moisture) to some extent but mainly its role as a filler helps keep the powder dry and free-flowing, preventing clumping. 3 Statement 2 is incorrect. Sodium silicate is added as a builder and anti-corrosion agent. While it does contribute to the overall alkalinity (which helps in cleaning), its primary purpose isn't solely maintaining alkalinity (other components like sodium carbonate contribute more significantly to this). Furthermore, sodium sulphate itself is neutral and doesn't maintain alkalinity. The main purpose mentioned in S1 (keeping powder dry via sodium sulphate's filler property) is a recognized function. 4 Based on the functions, statement 1 is a more accurate description of a primary purpose of adding sodium sulphate.

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