CDS 2026 (I) General Knowledge, question 26

Topic: Chemistry

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Q26

Which one among the following pairs of compound and chemical formula is not correctly matched ?

  1. (a) Bleaching powder : CaOCl2\text{CaOCl}_{2}
  2. (b) Soda ash : Na2CO3Na_{2}CO_{3}
  3. (c) Baking powder : NaHCl2\text{NaHCl}_{2}Correct answer
  4. (d) Plaster of Paris : 2CaSO4⋅H2O2\text{CaSO}_{4}\cdot H_{2}O

Solution.

Answer: (c) Baking powder : NaHCl2\text{NaHCl}_{2}

  1. NaHCl₂ is not the formula of baking powder.
  2. Baking powder is a mixture containing sodium hydrogen carbonate, NaHCO₃, and an edible acid, often with a starch component.
  3. The other formulae match the usual school-level representations; 2CaSO₄·H₂O expresses the same hydration ratio as CaSO₄·½H₂O.