Which of the following are isomers -

Options

A. Ethanol and ethoxy ethane
B. Methanol and methoxy methane
C. Propanoic acid and ethyl acetate
D. Propionaldehyde and acetone

Answer

To determine which pairs of compounds are isomers, we need to follow these steps:

### Step 1: Identify the chemical formulas of each compound in the options.
- **Option 1**: Ethanol (C2H6O) and Ethoxyethane (C4H10O)
- **Option 2**: Methanol (CH3OH) and Methoxymethane (CH3OCH3)
- **Option 3**: Propanoic acid (C3H6O2) and another compound (not specified in the transcript).
- **Option 4**: Propanal (C3H6O) and Acetone (C3H6O)

### Step 2: Compare the formulas for each pair.
- **Option 1**: Ethanol (C2H6O) vs. Ethoxyethane (C4H10O) - Different formulas, not isomers.
- **Option 2**: Methanol (CH3OH) vs. Methoxymethane (CH3OCH3) - Different formulas, not isomers.
- **Option 3**: Propanoic acid (C3H6O2) vs. another unspecified compound - Different formulas, not isomers.
- **Option 4**: Propanal (C3H6O) vs. Acetone (C3H6O) - Same formula, different structures, they are isomers.

### Step 3: Conclusion
The only pair that qualifies as isomers is found in **Option 4**: Propanal and Acetone.

### Final Answer
**Option 4: Propanal and Acetone are isomers.**

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