Which of the following acids are likely to form Zwitter ions?

Options

A.
B.
C.
D. All of the above

Answer

To determine which of the given acids are likely to form Zwitter ions, we need to understand what a Zwitter ion is. A Zwitter ion is a molecule that contains both positive and negative charges but is overall neutral. This typically occurs in amino acids, which have both an amine group (NH3+) and a carboxyl group (COO-).

### Step-by-Step Solution:

1. **Identify the Structure of Each Acid**:
- We need to analyze the structure of each acid provided in the options to see if they contain both a positively charged group and a negatively charged group.

2. **Analyze Option 1**:
- The structure contains a carboxylic acid group (-COOH) and an amine group (-NH2).
- If we remove a hydrogen from the carboxylic acid, it becomes negatively charged (-COO-), and if we protonate the amine group, it becomes positively charged (-NH3+).
- This results in a Zwitter ion with both positive and negative charges.

3. **Analyze Option 2**:
- The structure includes multiple amine groups and a carboxylic acid group.
- Similar to Option 1, upon deprotonation of the carboxylic acid and protonation of the amine group, we can form a Zwitter ion.
- Thus, this option also forms a Zwitter ion.

4. **Analyze Option 3**:
- This structure contains a phenolic group (-OH) and an amine group (-NH2).
- By deprotonating the phenolic group, it can become negatively charged (-O-) and protonating the amine group results in a positive charge (-NH3+).
- Therefore, this structure also forms a Zwitter ion.

5. **Conclusion**:
- Since all three options can form Zwitter ions, the answer is that all of the given acids are likely to form Zwitter ions.

### Final Answer:
**Option 4: All of the above.**