The molecule (s) that will have dipole moment is/are:

Options

A. `2,2` Dimethyl propane
B. trans-`2`-Pentene
C. cis -`3`- Hexene
D. `2,2,3,3`-Tetramethyl butane

Explanation

To determine which molecules have a dipole moment, we need to analyze the molecular structures and their symmetry. A dipole moment occurs when there is a separation of charge due to differences in electronegativity between atoms, and it is also influenced by the molecular geometry.

### Step-by-Step Solution:

1. **Analyze 2,2-Dimethylpropane:**
- Structure: 2,2-Dimethylpropane has a symmetrical structure.
- Symmetry: The molecule is symmetrical, meaning that the dipole moments from the different bonds will cancel each other out.
- Conclusion: The net dipole moment (μ net) is zero. **(No dipole moment)**

2. **Analyze Trans-2-pentene:**
- Structure: Trans-2-pentene has a different arrangement of groups on either side of the double bond.
- Dipole Moments: The dipole moments from the different groups do not cancel out completely due to the different substituents on either side.
- Conclusion: The net dipole moment (μ net) is not equal to zero. **(Has a dipole moment)**

3. **Analyze Cis-3-hexene:**
- Structure: Cis-3-hexene has a similar situation to trans-2-pentene but with a cis configuration.
- Dipole Moments: The dipole moments do not cancel out due to the presence of different groups on the same side of the double bond.
- Conclusion: The net dipole moment (μ net) is not equal to zero. **(Has a dipole moment)**

4. **Analyze 2,2,3,3-Tetramethylbutane:**
- Structure: This molecule has a bulky structure with multiple methyl groups.
- Symmetry: The arrangement of the methyl groups leads to a lack of symmetry in the distribution of charge.
- Conclusion: The net dipole moment (μ net) is not equal to zero. **(Has a dipole moment)**

### Final Conclusion:
The molecules that exhibit a dipole moment are:
- **Trans-2-pentene (B)**
- **Cis-3-hexene (C)**
- **2,2,3,3-tetramethylbutane (D)**

Thus, the correct answer is **B, C, and D**.

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