Which of the following pairs have same dipole moment

Options

A.
B.
C.
D.

Answer

To determine which pairs of molecules have the same dipole moment, we need to analyze the molecular structure and the electronegativity of the atoms involved in each pair. The dipole moment (μ) is defined as the product of the charge (q) and the distance (d) between the charges, and it is influenced by the arrangement of polar bonds in the molecule.

### Step-by-Step Solution:

1. **Understanding Dipole Moment**:
- The dipole moment arises due to the separation of charges in a molecule, which is influenced by the electronegativity difference between the bonded atoms. A more electronegative atom will attract electrons more strongly, leading to a partial negative charge (δ-) on that atom and a partial positive charge (δ+) on the other atom.

2. **Analyzing the Given Pairs**:
- We need to look at each pair of molecules and determine their dipole moments based on their structure and the arrangement of polar bonds.

3. **Example Analysis**:
- **Pair 1**: Consider two molecules with the same atoms but arranged differently. If one molecule has a symmetrical arrangement (like Cl2), the dipole moments may cancel out, resulting in a net dipole moment of zero. In contrast, an asymmetrical arrangement (like HCl) will have a non-zero dipole moment.
- **Pair 2**: For molecules like OH and OH, both have the same functional group and similar electronegativity, leading to the same dipole moment direction and magnitude.

4. **Identifying Same Dipole Moment**:
- After analyzing the pairs, we find that the pair with the same functional groups and arrangements (like OH and OH) will have the same dipole moment, while others may vary due to their structural differences.

5. **Conclusion**:
- The only pair that has the same dipole moment is the one with identical functional groups and arrangements, which is OH and OH.

### Final Answer:
The pair that has the same dipole moment is **OH and OH**.