Answer to Question #256584 in General Chemistry for nick

Question

carbon dioxide is an acidic oxide that reacts with aqueous calcium hydroxide which type or reaction takes place?

Answer 1

The reaction of calcium  hydroxide with carbon dioxide as a precipitation reaction because in this reaction a white solid precipitate named calcium carbonate is obtained. Calcium hydroxide is otherwise called limewater.

Limewater is weak calcium hydroxide. When you bubble CO2 through it, it goes cloudy. This is the standard test for CO2.

What’s going on is that the calcium hydroxide is being converted back into calcium carbonate, from which it originally came, most probably.

Limestone contains mostly calcium carbonate, but in its pure solid form it's just called chalk!

Chalk is not dangerous. The reactions involved are;

CaCO3 (heat)→ CaO + CO2 (heating limestone)

CaO + H2O → Ca(OH)2 (limewater)

Ca(OH)2 + CO2 → CaCO3 + H2O (chalk + water)