Identify `X` and `Y` in the following reactions .
`PbS underset("in air") overset (Heat) (rarr) (X)`
`(X) + PbS overset (Y) (rarr) Pb+SO_(2)`.

Explanation

To identify `X` and `Y` in the given reactions, we will analyze each reaction step by step.

### Step 1: Analyze the first reaction
The first reaction is:
\[ \text{PbS (in air) + Heat} \rightarrow X \]

When lead sulfide (PbS) is heated in the presence of air, it can react with oxygen to form either lead(II) oxide (PbO) or lead(II) sulfate (PbSO₄). Therefore, we have two possible candidates for `X`:
- \( X = \text{PbO} \)
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