Name the valuable halogen impurities present in chile salt petre `(NaNO_3)`.

Explanation

To answer the question about the valuable halogen impurities present in Chile saltpetre (NaNO₃), we can follow these steps:

### Step 1: Identify Chile Saltpetre
Chile saltpetre is the common name for sodium nitrate, which has the chemical formula NaNO₃. It is a naturally occurring mineral that is primarily used as a fertilizer and in the production of explosives.

**Hint:** Remember that Chile saltpetre is synonymous with sodium nitrate.

### Step 2: Determine the Halogen Impurities
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