Metamerism is shown by -

Options

A. Diethyl ether and n-propyl methyl ether
B. Ethyl alcohol and diethyl ether
C. Acetone and propionaldehyde
D. Propionic acid and acetic acid

Answer

To determine which compounds exhibit metamerism, we first need to understand what metamerism is.

### Step-by-Step Solution:

1. **Definition of Metamerism**:
Metamerism is a type of isomerism that occurs when there is an unequal distribution of carbon atoms on either side of a functional group in a molecule. This typically applies to compounds with non-terminal functional groups, such as ethers and ketones.

2. **Identifying Non-terminal Functional Groups**:
- Non-terminal functional groups are those that are not located at the end of the carbon chain. Examples include ethers (R-O-R') and ketones (R-C(=O)-R').
- Terminal functional groups, such as alcohols (R-OH), carboxylic acids (R-COOH), and aldehydes (R-CHO), do not exhibit metamerism.

3. **Analyzing the Options**:
- **Option 1: Diethyl ether (CH3-CH2-O-CH2-CH3)**: This compound has the ether functional group and can show metamerism. For example, it can exist in another form like CH3-O-CH(CH3)-CH2, where the distribution of carbon atoms around the oxygen is different.
- **Option 2: Alcohol (e.g., Ethanol, CH3-CH2-OH)**: This is a terminal functional group and does not show metamerism.
- **Option 3: Acetone (CH3-CO-CH3)**: This is a ketone, but it cannot show metamerism because the carbon atoms cannot be rearranged without changing the functional group.
- **Option 4: Propionic acid (CH3-COOH)**: This is also a terminal functional group and will not show metamerism.

4. **Conclusion**:
Based on the analysis, the only compound that shows metamerism is **Option 1: Diethyl ether**.

### Final Answer:
Metamerism is shown by **Option 1: Diethyl ether**.

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