Which of the following can show tautomerism here.

Options

A.
B.
C.
D. Both B and C

Answer

To determine which compounds can show tautomerism, we need to understand the concept of tautomerism itself. Tautomerism is a chemical phenomenon where a compound can exist in two or more forms that are interconvertible, typically involving the migration of a hydrogen atom and a shift in the position of a double bond.

### Step-by-Step Solution:

1. **Identify the Compounds**: First, we need to look at the given options (A, B, C, D) and identify their structures. Tautomerism usually occurs between a keto form (with a carbonyl group) and an enol form (with an alcohol group).

2. **Analyze Each Compound**:
- **Option A**: Check if it has a carbonyl group (C=O) and if a hydrogen can migrate to form an enol. If the structure does not allow for hydrogen migration or lacks a carbonyl group, it cannot show tautomerism.
- **Option B**: Look for a carbonyl group and assess if hydrogen migration is possible. If it can shift to form an enol, then this compound can show tautomerism.
- **Option C**: Similar to Option B, check for the presence of a carbonyl group and the possibility of hydrogen migration to form an enol.
- **Option D**: Again, check for the presence of a carbonyl group and the potential for hydrogen migration.

3. **Determine Tautomeric Forms**:
- For options that can show tautomerism, write down the keto form and the corresponding enol form to visualize the hydrogen migration.
- For example, if a compound is CH3C(=O)CH3 (keto form), the enol form would be CH2=C(OH)CH3 after hydrogen migration.

4. **Conclusion**: After analyzing each option, determine which compounds can interconvert between keto and enol forms.

5. **Final Answer**: Based on the analysis, identify the options that can show tautomerism. In this case, it was determined that options B and C can show tautomerism.