Which gas is produced when sodium hydrogen carbonate NaHCO₃ is heated?
Answer and explanation
Correct answer: Carbon dioxide
On heating, sodium hydrogen carbonate undergoes thermal decomposition: 2NaHCO₃ → Na₂CO₃ + H₂O + CO₂. The gas released is therefore carbon dioxide. It can be identified because it turns limewater milky, although this test is not required to select the answer. Oxygen, hydrogen, and chlorine are not products of this decomposition, so option B is correct.
Frequently asked questions
What is the correct answer to this question?
Carbon dioxide
Why is this the correct answer?
On heating, sodium hydrogen carbonate undergoes thermal decomposition: 2NaHCO₃ → Na₂CO₃ + H₂O + CO₂. The gas released is therefore carbon dioxide. It can be identified because it turns limewater milky, although this test is not required to select the answer. Oxygen, hydrogen, and chlorine are not products of this decomposition, so option B 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.
