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Science — CBSE Class 10 board question

Q1. [1]
Select washing soda from the following :
  1. (a) NaHCO₃
  2. (b) Na₂CO₃.5H₂O
  3. (c) Na₂CO₃.10H₂O
  4. (d) NaOH
Previously asked in CBSE board exam
2023 31/1/1 Q6
Generated by claude-sonnet-4-6 · 2026-06-15 06:46 · grounding rag
Model Answer

(c) Na₂CO₃.10H₂O

Washing soda is sodium carbonate decahydrate with the formula Na₂CO₃.10H₂O.

Explanation

Washing soda = Na₂CO₃.10H₂O. NaHCO₃ is baking soda, NaOH is caustic soda, and Na₂CO₃.5H₂O is not the correct hydrated form. Examiners expect you to know the exact formula including the water of crystallisation (10H₂O).

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