If baking soda is heated, what will be the main substance in the solid residue?
Answer and explanation
Correct answer: Sodium carbonate
The governing concept is thermal decomposition of a hydrogen carbonate. On heating, sodium hydrogen carbonate decomposes according to 2NaHCO₃ → Na₂CO₃ + CO₂ + H₂O. Carbon dioxide and water leave as gases, so sodium carbonate remains as the main solid residue. Sodium chloride and calcium salts are not products of this reaction; therefore option A is correct.
Frequently asked questions
What is the correct answer to this question?
Sodium carbonate
Why is this the correct answer?
The governing concept is thermal decomposition of a hydrogen carbonate. On heating, sodium hydrogen carbonate decomposes according to 2NaHCO₃ → Na₂CO₃ + CO₂ + H₂O. Carbon dioxide and water leave as gases, so sodium carbonate remains as the main solid residue. Sodium chloride and calcium salts are not products of this reaction; therefore option A is correct.
Which subject and chapter does this question cover?
This is a Class 10 Science question. Chapter: Chemical Substances – Nature and Behaviour. Topic: Acids, Bases, and Salts.
