Question

When carbon dioxide gas is passed through lime water,

• A. calcium hydroxide is formed.
• B. white precipitate of $\text{CaO}$ is formed.
• C. white precipitate of ${\text{CaCO}}_3$ is formed.
• D. colour of lime water disappears.

Answer 1

The correct option is C white precipitate of ${\text{CaCO}}_3$ is formed.

When ${\text{CO}}_2$ is passed through lime water, a white precipitate of ${\text{CaCO}}_3$ is formed, which turns lime water milky. The reaction occurs as follows:

${\text{Ca(OH)}}_2\text{(aq)}+{\text{CO}}_2\text{(g)}\to {\text{CaCO}}_3\text{(s)}\downarrow +{\text{H}}_2\text{O}\text{(l)}$