Question 18 of 34intermediate💡 UnderstandShort Answer2 marks

What will happen if a solution of sodium hydrogencarbonate is heated? Give the equation of the reaction involved.

Correct Answer

When a solution of sodium hydrogencarbonate is heated, it undergoes thermal decomposition to form sodium carbonate, water, and carbon dioxide gas. The carbon dioxide gas is released during this reaction.

The balanced chemical equation for this reaction is:

2NaHCO3→HeatNa2CO3+H2O+CO22\text{NaHCO}_3 \xrightarrow{\text{Heat}} \text{Na}_2\text{CO}_3 + \text{H}_2\text{O} + \text{CO}_2

This reaction is significant in cooking, where the carbon dioxide produced helps bread or cake to rise, making them soft and spongy.

Exercise: QUESTIONS (Section 2.4) | Q: 4 | (Page Page 17)
For More Understanding

Explanation

The question tests the student's understanding of thermal decomposition of sodium hydrogencarbonate (baking soda). The textbook explicitly provides the decomposition reaction showing that heating NaHCO₃ produces sodium carbonate (Na₂CO₃), water (H₂O), and carbon dioxide (CO₂). This is a 2-mark question requiring both the observation and the balanced chemical equation.

Solution Steps

  1. Step 1: Identify that sodium hydrogencarbonate decomposes on heating.

  2. Step 2: Write the products formed: sodium carbonate, water, and carbon dioxide.

  3. Step 3: Write the balanced chemical equation: 2NaHCO₃ → Na₂CO₃ + H₂O + CO₂

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