Why pure `PH_3` does not burn in air but impure sample does ?

Explanation

To understand why pure PH₃ (phosphine) does not burn in air while an impure sample does, we can break down the explanation into several steps:

### Step 1: Understanding Pure PH₃
- Pure phosphine (PH₃) is a stable compound that does not readily react with oxygen in the air at room temperature. This stability is due to the lack of reactive species or impurities that could facilitate combustion.

### Step 2: The Role of Impurities
- An impure sample of PH₃ may contain other phosphorus-containing compounds, such as diphosphine (P₂H₄). These impurities can significantly alter the chemical behavior of the sample.

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