The chemical X is a hydroxide of a divalent metal. On treating this hydroxide with `CO_2`, a milky white precipitate of Y is formed. The precipitate turns to colourless solution by the excess passage of `CO_2`. This colourless solution again gives milky white precipitate Y on heating. Identify X and Y and also give necessary equations.

Explanation

To solve the problem step by step, we need to identify the chemicals involved and the reactions that occur when the hydroxide of a divalent metal is treated with carbon dioxide (CO₂).

### Step 1: Identify the Hydroxide (X)
The question states that chemical X is a hydroxide of a divalent metal. Divalent metals have a valency of +2. A common divalent metal is calcium (Ca). Therefore, the hydroxide of calcium is:

\[ X = \text{Calcium hydroxide} = \text{Ca(OH)}_2 \]
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