Science — AI-generated practice question

Baking powder is a mixture of baking soda (sodium hydrogen carbonate, NaHCO₃) and a mild edible acid such as tartaric acid.

How it makes bread/cake soft and spongy:
When baking powder is heated during baking, the acid reacts with sodium hydrogen carbonate to release carbon dioxide (CO₂) gas:

$$\text{NaHCO}_3 + \text{acid} \xrightarrow{\Delta} \text{CO}_2 + \text{H}_2\text{O} + \text{salt}$$

The CO₂ gas produced gets trapped in the dough, forming bubbles. This causes the dough to rise and become soft and spongy. Baking powder is preferred over baking soda alone because no bitter taste is left — the acid neutralises the sodium carbonate formed.

Source: Chapter 2, Acids, Bases and Salts

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• Key points examiners look for: Definition of baking powder (mixture, name both components), the chemical reaction producing CO₂, and how CO₂ makes it spongy.
• The equation/reaction is important for full marks — don't skip it.
• Mentioning why baking powder is used instead of baking soda alone (no bitter taste) is a bonus point that can secure full marks.
• Note: The source passages provided did not directly cover this topic, but this is standard NCERT Chapter 2 content examiners expect.