Which of the following molecules does not have net dipole moment?

Options

A. `IB r `
B. `CHCl_(3)`
C. `CH_(2)Cl_(2)`
D. `BF_(3)`

Explanation

To determine which of the following molecules does not have a net dipole moment, we need to analyze each molecule's structure and symmetry. A molecule has a net dipole moment if there is an uneven distribution of electron density, which usually arises from differences in electronegativity between atoms.

### Step-by-Step Solution:

1. **Identify the Molecules**: We need to analyze the dipole moments of the given molecules. Let's assume the options are:
- A) IBr (Iodine Monobromide)
- B) CHCl3 (Chloroform)
- C) CH2Cl2 (Dichloromethane)
- D) BF3 (Boron Trifluoride)

2. **Analyze IBr**:
- **Structure**: Iodine (I) is bonded to Bromine (Br).
- **Electronegativity**: Br is more electronegative than I.
- **Dipole Moment**: There is a dipole moment directed from I to Br. Thus, IBr has a net dipole moment (μ ≠ 0).

3. **Analyze CHCl3**:
- **Structure**: Tetrahedral structure with one carbon (C) atom bonded to three chlorine (Cl) atoms and one hydrogen (H) atom.
- **Electronegativity**: Cl is more electronegative than C and H.
- **Dipole Moment**: The dipole moments from the three Cl atoms do not cancel out due to the asymmetrical arrangement. Thus, CHCl3 has a net dipole moment (μ ≠ 0).

4. **Analyze CH2Cl2**:
- **Structure**: Tetrahedral structure with one carbon atom bonded to two chlorine atoms and two hydrogen atoms.
- **Electronegativity**: Cl is more electronegative than C and H.
- **Dipole Moment**: The dipole moments from the two Cl atoms do not cancel out completely due to the asymmetrical arrangement. Thus, CH2Cl2 has a net dipole moment (μ ≠ 0).

5. **Analyze BF3**:
- **Structure**: Trigonal planar structure with one boron (B) atom bonded to three fluorine (F) atoms.
- **Electronegativity**: F is more electronegative than B.
- **Dipole Moment**: The three dipole moments from the F atoms are equal in magnitude and symmetrically arranged, leading to cancellation. Thus, BF3 has no net dipole moment (μ = 0).

6. **Conclusion**: Among the given options, the molecule that does not have a net dipole moment is **BF3**.

### Final Answer:
The correct option is **D) BF3**.