Which of the following reactions would give propanal ?

Options

A. Ethyl propanoate + DBAH (diisobutyl aluminium hydride). `[(i-C_(4)H_(9))_(2)AlH)]` at `-70^(@)C`, followed by hydrolysis.
B. Propyl propanoate `+ DIBAL-H//H_(2)O`
C. Ethyl cyanide `+ DBAH`
D. Propanoyl chloride `+ LBAH`

Explanation

To determine which of the given reactions would yield propanal (C2H5CHO), we will analyze each reaction step by step.

### Step 1: Analyze Reaction A
- **Reactants**: Ethyl propanoate (C2H5C(=O)O) and a weak reducing agent (DBH).
- **Mechanism**: The weak reducing agent reduces the ester functional group. The carbonyl bond (C=O) breaks, and hydrogen atoms are added to the carbon and oxygen.
- **Products**: The reaction yields propanal (C2H5CHO) and ethanol (C2H5OH).
- **Conclusion**: Reaction A produces propanal.

### Step 2: Analyze Reaction B
- **Reactants**: Propyl propanoate (C3H7C(=O)O) and a weak reducing agent (DBH).
- **Mechanism**: Similar to Reaction A, the carbonyl group is reduced.
- **Products**: The reaction yields propanal (C2H5CHO) and propanol (C3H7OH).
- **Conclusion**: Reaction B also produces propanal.

### Step 3: Analyze Reaction C
- **Reactants**: Ethyl cyanide (C2H5C≡N) and a weak reducing agent (DBH).
- **Mechanism**: The weak reducing agent reduces the nitrile group (C≡N) to an aldehyde.
- **Products**: The reaction yields propanal (C2H5CHO) and ammonia (NH3).
- **Conclusion**: Reaction C produces propanal.

### Step 4: Analyze Reaction D
- **Reactants**: Propanoyl chloride (C2H5C(=O)Cl) and a weak reducing agent (LBAH).
- **Mechanism**: The carbonyl group is reduced similarly to the previous reactions.
- **Products**: The reaction yields propanal (C2H5CHO) and hydrochloric acid (HCl).
- **Conclusion**: Reaction D also produces propanal.

### Final Conclusion
All four reactions (A, B, C, and D) yield propanal (C2H5CHO).

### Summary of Results
- **Reactions that produce propanal**: A, B, C, and D.