Which of the following is a polar molecule ?

Options

A. Para dichiorobenzene
B. Carbon tetrachloride
C. Tetrachloroethene
D.

Answer

To determine which of the given molecules is a polar molecule, we need to analyze the dipole moments of each molecule. A polar molecule has a net dipole moment that is not equal to zero, while a non-polar molecule has a net dipole moment of zero.

### Step-by-Step Solution:

1. **Identify the Molecules**: We need to analyze the following molecules:
- Para-dichlorobenzene (C6H4Cl2)
- Carbon tetrachloride (CCl4)
- Tetrachloroethene (C2Cl4)
- Para-hydroxyphenol (C6H5(OH))

2. **Analyze Para-dichlorobenzene**:
- In para-dichlorobenzene, the chlorine atoms are positioned opposite each other on the benzene ring.
- The dipole moments from each Cl atom will cancel each other out due to symmetry.
- **Conclusion**: The dipole moment is zero, making it a non-polar molecule.

3. **Analyze Carbon Tetrachloride (CCl4)**:
- In CCl4, the carbon atom is at the center with four chlorine atoms symmetrically arranged around it.
- The dipole moments from each Cl atom also cancel each other out due to symmetry.
- **Conclusion**: The dipole moment is zero, making it a non-polar molecule.

4. **Analyze Tetrachloroethene (C2Cl4)**:
- In tetrachloroethene, the structure is symmetrical with two Cl atoms on each carbon.
- The dipole moments from the chlorine atoms will cancel each other out.
- **Conclusion**: The dipole moment is zero, making it a non-polar molecule.

5. **Analyze Para-hydroxyphenol (C6H5(OH))**:
- In para-hydroxyphenol, the hydroxyl (OH) groups are positioned on opposite sides of the benzene ring.
- However, the arrangement of the OH groups is not symmetrical due to the presence of hydrogen atoms, which leads to a net dipole moment.
- The bond angle of the C-O-H is not symmetrical, contributing to a non-zero dipole moment.
- **Conclusion**: The dipole moment is not zero, making it a polar molecule.

### Final Answer:
The polar molecule among the given options is **Para-hydroxyphenol (C6H5(OH))**.

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