Why is it not suitable to leave sodium hydroxide open in air?
Answer and explanation
Correct answer: It can react with moisture and carbon dioxide
Sodium hydroxide is deliquescent, so it absorbs moisture from air and may become wet or form a solution. It also reacts with atmospheric carbon dioxide, producing sodium carbonate and water: 2NaOH + CO₂ → Na₂CO₃ + H₂O. These changes alter the substance and its concentration, so it should be stored in a tightly closed container. Hence option A is correct; the other statements describe impossible effects.
Frequently asked questions
What is the correct answer to this question?
It can react with moisture and carbon dioxide
Why is this the correct answer?
Sodium hydroxide is deliquescent, so it absorbs moisture from air and may become wet or form a solution. It also reacts with atmospheric carbon dioxide, producing sodium carbonate and water: 2NaOH + CO₂ → Na₂CO₃ + H₂O. These changes alter the substance and its concentration, so it should be stored in a tightly closed container. Hence option A is correct; the other statements describe impossible effects.
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.
