Which of the following molecules will have polar bonds but zero dipole moment?

Options

A. `O_(2)`
B. `CHCl_(3)`
C. `CF_(4)`
D. none of these

Answer

To determine which molecule has polar bonds but a zero dipole moment, we need to analyze the molecular geometry and the electronegativity of the atoms involved in each molecule.

### Step-by-Step Solution:

1. **Understanding Polar Bonds:**
- A polar bond occurs when there is a difference in electronegativity between the two atoms forming the bond. This results in an uneven distribution of electron density, creating a dipole moment.

2. **Identifying Molecules:**
- We need to consider the given molecules: O2, CHCl3, and CF4.

3. **Analyzing O2:**
- O2 consists of two oxygen atoms. Since both atoms are the same, there is no difference in electronegativity. Therefore, O2 has nonpolar bonds and a dipole moment of zero.

4. **Analyzing CHCl3 (Chloroform):**
- In CHCl3, carbon is bonded to three chlorine atoms and one hydrogen atom. Chlorine is more electronegative than carbon, creating polar bonds. The dipole moments from the three C-Cl bonds do not cancel out due to the asymmetrical shape of the molecule, resulting in a net dipole moment that is not zero.

5. **Analyzing CF4 (Carbon Tetrafluoride):**
- In CF4, carbon is bonded to four fluorine atoms. Fluorine is the most electronegative element, creating polar bonds. However, the molecular geometry of CF4 is tetrahedral, and the dipole moments from the four C-F bonds are symmetrically arranged. The dipole moments cancel each other out, resulting in a net dipole moment of zero.

6. **Conclusion:**
- Among the molecules analyzed, CF4 has polar bonds but a zero dipole moment due to its symmetrical tetrahedral shape.

### Final Answer:
- **CF4** is the molecule that has polar bonds but a zero dipole moment.