When carbon dioxide is passed through lime water, which colour precipitate is obtained?
Show answer & explanation
Correct answer: D
Explanation
Correct Answer: Option 4 (White)
Explanation:
When carbon dioxide (CO₂) is passed through limewater (calcium hydroxide), calcium carbonate (CaCO₃) is formed, which is a white precipitate. This is why limewater turns milky.
Additional Facts:
Reaction: CO₂ + Ca(OH)₂ → CaCO₃ ↓ + H₂O
When more CO₂ is passed through, calcium bicarbonate is formed, which clears the solution again.
This test is used to identify CO₂ gas.
Possible questions for the upcoming exam:
Why does limewater turn milky?
(Answer: Due to the formation of CaCO₃)
What is the color of calcium carbonate?
(Answer: White)