Science — AI-generated practice question

Baking soda (sodium hydrogencarbonate, NaHCO₃) is heated to obtain washing soda (sodium carbonate, Na₂CO₃). The reaction is:

$$2\text{NaHCO}_3 \xrightarrow{\Delta} \text{Na}_2\text{CO}_3 + \text{H}_2\text{O} + \text{CO}_2$$

Na₂CO₃ is then recrystallised to get washing soda, Na₂CO₃·10H₂O.

Source: Acids, Bases and Salts, Chapter 2

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• Examiners expect the chemical name and formula of both baking soda and washing soda.
• The balanced chemical equation with heat symbol (Δ) is essential for full marks.
• Mentioning recrystallisation (addition of water of crystallisation) completes the answer and shows awareness that washing soda is the decahydrate.
• Do not confuse baking soda (NaHCO₃) with washing soda (Na₂CO₃·10H₂O) — both names and formulas must be correct.