Dipole moment is possessed by (one or more)

Options

A. 1,4 -Dichlorobenzene
B. cis 1, 2-Dichloroethene
C. trans-1, 2-Dichloroethene
D. trans-2, 3-Dichloro-2-pentene

Explanation

To determine which compounds possess a dipole moment, we need to analyze the molecular geometry and the electronegativity of the atoms involved in each compound. A dipole moment occurs when there is a separation of charge due to differences in electronegativity between atoms, leading to a polar bond.

### Step-by-Step Solution:

1. **Identify the Compounds**:
We have four compounds to analyze:
- 1,4-dichlorobenzene
- 1,2-dichloroethene
- trans-1,2-dichloroethene
- trans-2,3-dichloroethene

2. **Analyze 1,4-Dichlorobenzene**:
- Structure: In this compound, the two chlorine atoms are located opposite each other on the benzene ring.
- Polarity: The dipoles from the two Cl atoms cancel each other out due to symmetry.
- Conclusion: **Dipole Moment = 0** (no dipole moment).

3. **Analyze 1,2-Dichloroethene**:
- Structure: The chlorine atoms are on adjacent carbons.
- Polarity: The dipoles from the two Cl atoms do not cancel out as they are not symmetrically placed.
- Conclusion: **Dipole Moment ≠ 0** (has a dipole moment).

4. **Analyze trans-1,2-Dichloroethene**:
- Structure: The chlorine atoms are on opposite sides of the double bond.
- Polarity: The dipoles from the two Cl atoms cancel each other out due to symmetry.
- Conclusion: **Dipole Moment = 0** (no dipole moment).

5. **Analyze trans-2,3-Dichloroethene**:
- Structure: The chlorine atoms are on opposite sides of the double bond, with ethyl groups on the other sides.
- Polarity: The dipoles from the two Cl atoms do not cancel out due to the presence of the ethyl groups.
- Conclusion: **Dipole Moment ≠ 0** (has a dipole moment).

### Final Conclusion:
The compounds that possess a dipole moment are:
- 1,2-dichloroethene
- trans-2,3-dichloroethene