What is the colour of the precipitate obtained by passing CO₂ gas thro

What is the colour of the precipitate obtained by passing CO₂ gas through lime water ?

Green

Blue

White

Brown

Answer is Right!

Answer is Wrong!

This question was previously asked in

UPSC NDA-2 – 2021

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Lime water is an aqueous solution of calcium hydroxide (Ca(OH)₂). When carbon dioxide (CO₂) gas is passed through lime water, it reacts with calcium hydroxide to form calcium carbonate (CaCO₃) and water. Calcium carbonate is insoluble in water and precipitates out as a fine suspension, which appears white.

– Reaction: Ca(OH)₂(aq) + CO₂(g) → CaCO₃(s) + H₂O(l)
– Calcium carbonate (CaCO₃) is the precipitate formed.
– Calcium carbonate is a white solid.

If CO₂ is passed through lime water for a prolonged period, the white precipitate of calcium carbonate dissolves as it reacts further with CO₂ and water to form soluble calcium bicarbonate (Ca(HCO₃)₂): CaCO₃(s) + H₂O(l) + CO₂(g) → Ca(HCO₃)₂(aq).

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