To solve the question of identifying the incorrect statement among the given options, we will analyze each statement step-by-step.
### Step-by-Step Solution:
1. **Understanding the First Statement**:
- The first statement claims that "in an electrolysis experiment, alpha amino acids migrate at the isoelectric point towards electrodes."
- At the isoelectric point, alpha amino acids exist predominantly in their zwitterionic form, which is neutral. Since neutral molecules do not migrate towards electrodes during electrolysis, this statement is incorrect.
2. **Analyzing the Second Statement**:
- The second statement states, "para amino benzenesulfonic acid exists as a dipolar ion while para amino benzoic acid does not."
- Para amino benzenesulfonic acid contains a sulfonic acid group (–SO3H), which can donate a proton to the amino group (–NH2), allowing it to exist in a zwitterionic form. In contrast, para amino benzoic acid (which has a carboxylic acid group) does not have the same capability to form a dipolar ion. Thus, this statement is correct.
3. **Evaluating the Third Statement**:
- The third statement claims, "sulfonylic acid is soluble in base but not in acid."
- Sulfonylic acid (para amino benzenesulfonic acid) can donate a proton from the –NH3+ group in a basic medium, forming a salt and thus is soluble in bases. However, in acidic conditions, it cannot accept a proton due to the weak basicity of the sulfonate group. Therefore, this statement is also correct.
4. **Reviewing the Fourth Statement**:
- The fourth statement states, "NH3+ CH2COH is more acidic than RCH2COH."
- The presence of the –NH3+ group (which is a strong acid) enhances the acidity of the compound compared to RCH2COH, which lacks this additional acidic group. Hence, this statement is also correct.
### Conclusion:
After analyzing all the statements, we conclude that the first statement is the incorrect one.
### Final Answer:
The incorrect statement is: **"In an electrolysis experiment, alpha amino acids migrate at the isoelectric point towards electrodes."**
---
