Which of the following options is incorrect?

Options

A. `pK_(a_(1))` cis but-2-ene dioic acid gt trans but-2-ene dioic acid
B. dipole moment
C. Stability
D. Basicity

Explanation

To solve the question of identifying the incorrect statement among the given options, we will analyze each option step-by-step.

### Step 1: Analyze Option A
**Statement:** The pKa value of cis-but-2-ene dioic acid is greater than that of trans-but-2-ene dioic acid.

- **Explanation:**
- In cis-but-2-ene dioic acid, intramolecular hydrogen bonding occurs due to the proximity of the carboxylic acid groups. This bonding stabilizes the molecule, making it less acidic, which results in a higher pKa value.
- In trans-but-2-ene dioic acid, there is no such intramolecular hydrogen bonding, leading to greater acidity and thus a lower pKa value.

- **Conclusion:** This statement is correct.

### Step 2: Analyze Option B
**Statement:** The dipole moment of cis-but-2-ene is greater than that of trans-but-2-ene.

- **Explanation:**
- In cis-but-2-ene, the polar groups (like CH3 and CN) are on the same side, which adds to the overall dipole moment.
- In trans-but-2-ene, these groups are on opposite sides, which tends to cancel out their dipole moments, resulting in a lower overall dipole moment.

- **Conclusion:** This statement is correct.

### Step 3: Analyze Option C
**Statement:** The stability order of cis and trans dichloroethene is such that trans is more stable than cis.

- **Explanation:**
- The cis form of dichloroethene has chlorine atoms closer together, which can lead to steric hindrance and repulsion. However, it can also allow for intramolecular interactions that can stabilize the molecule.
- The trans form has the chlorine atoms further apart, which reduces steric hindrance but does not allow for the same intramolecular attractions.
- Generally, it is accepted that the trans form is more stable due to less steric hindrance, but the argument presented in the video suggests that the cis form may have stabilizing interactions that are not considered in the traditional view.

- **Conclusion:** This statement is incorrect based on the argument presented in the video.

### Step 4: Analyze Option D
**Statement:** The basicity of the amine group is greater when attached to the vinylic carbon than when attached to the allylic carbon.

- **Explanation:**
- When the amine group is attached to the vinylic carbon, its lone pairs can participate in resonance, making them less available for protonation and thus less basic.
- When attached to the allylic carbon, the lone pairs are not involved in resonance with the double bond, making them more available for protonation and thus more basic.

- **Conclusion:** This statement is correct.

### Final Conclusion
After analyzing all the options, we find that the incorrect statement is **Option C**.