Give the chemical reaction when ethanal is heated with hydrogen iodide and red phosphorus under high pressure.

Explanation

To determine the chemical reaction when ethanal (acetaldehyde) is heated with hydrogen iodide (HI) and red phosphorus (P) under high pressure, we can follow these steps:

### Step 1: Identify the Reactants
The reactants in this reaction are:
- Ethanal (acetaldehyde), which has the chemical formula CH₃CHO.
- Hydrogen iodide (HI).
- Red phosphorus (P).

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