When carbon dioxide gas is passed through freshly prepared lime water, the limewater turns milky.

Question

Give scientific reasons:

When carbon dioxide gas is passed through freshly prepared lime water, the limewater turns milky.

Answer 1

• Limewater traditionally means a weak solution of the alkali calcium hydroxide Ca(OH)₂ . 
• When CO₂ is passed through limewater, it reacts with calcium hydroxide to form insoluble particulates (precipitate of calcium carbonate (CaCO₃).
• Calcium carbonate is weak basic salt and this gives a milky white precipitate.

• Hence, lime water turns milky when CO₂ gas is passed through it.