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Railways PYQCBT 1 2016

RRB NTPC · Question 18

Which among the followings is not the application of Washing Soda?

  1. It is used for removing the permanent hardness of the water.

  2. It is used in the manufacture of sodium compounds such as borax.

  3. For disinfecting drinking water to make it free of germs.

  4. It is used in glass, soap and paper industries.

Show answer & explanation

Answer: (C) For disinfecting drinking water to make it free of germs.

Explanation

Washing soda (sodium carbonate decahydrate, Na₂CO₃·10H₂O) removes permanent hardness of water, is used to make sodium compounds such as borax, and is used in glass, soap and paper industries. It is not a disinfectant; drinking water is disinfected with chlorine or bleaching powder.