The compound which can show tautomerism

Options

A. `CH_(3)CH_(2)-NO_(2)`
B. `CH_(3)-underset(O)underset(||)C-NH_(2)`
C. `CH_(3)-underset(O)underset(||)C-CH_(3)`
D. All of these

Answer

To determine which compound can show tautomerism, we need to analyze the given compounds. Tautomerism is a type of isomerism where compounds can readily interconvert between two forms, typically involving the relocation of a hydrogen atom and a shift in a double bond.

### Step-by-Step Solution:

1. **Identify the Compounds**:
- The first compound is CH3-CH(NO2)-H (a nitro compound).
- The second compound is not specified in the transcript, but we will consider it later.
- The third compound is also not specified but is implied to be related to the first compound.

2. **Analyze the First Compound**:
- The structure CH3-CH(NO2)-H has a nitro group (NO2) attached to a carbon atom that also has a hydrogen atom.
- The presence of the nitro group can facilitate tautomerism due to its ability to stabilize a negative charge.

3. **Tautomerism Mechanism**:
- In the presence of the nitro group, a hydrogen atom can shift from the carbon to the oxygen of the nitro group, resulting in a resonance structure.
- This shift creates a new compound where the hydrogen is now bonded to the oxygen, and a double bond is formed between the carbon and the nitrogen.

4. **Identify the Forms**:
- The original form is known as the keto form (with the carbon-nitrogen double bond).
- The new form after tautomerism is known as the enol form (with the hydrogen now on the oxygen).

5. **Conclusion**:
- The compound CH3-CH(NO2)-H can show tautomerism because it can interconvert between its keto and enol forms.

### Final Answer:
The compound that can show tautomerism is CH3-CH(NO2)-H.