Why can sodium hydroxide slowly form carbonate when left open in air?
Answer and explanation
Correct answer: Because it reacts with carbon dioxide from air
Sodium hydroxide is hygroscopic and can absorb moisture, but it also absorbs carbon dioxide from air. The absorbed carbon dioxide reacts with sodium hydroxide, for example: 2NaOH + CO₂ → Na₂CO₃ + H₂O. Therefore option A is correct. Nitrogen, oxygen, and noble gases do not explain the gradual formation of sodium carbonate under ordinary storage conditions.
Frequently asked questions
What is the correct answer to this question?
Because it reacts with carbon dioxide from air
Why is this the correct answer?
Sodium hydroxide is hygroscopic and can absorb moisture, but it also absorbs carbon dioxide from air. The absorbed carbon dioxide reacts with sodium hydroxide, for example: 2NaOH + CO₂ → Na₂CO₃ + H₂O. Therefore option A is correct. Nitrogen, oxygen, and noble gases do not explain the gradual formation of sodium carbonate under ordinary storage conditions.
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.
