Which of the following molecule has highest dipole moment?

Options

A. `BF_(3)`
B. `NH_(3)`
C. `NF_(3)`
D. `B_(2)H_(6)`

Answer

To determine which molecule has the highest dipole moment among the given options, we will analyze the molecular geometry and electronegativity of the atoms involved in each molecule.

### Step-by-Step Solution:

1. **Identify the Molecules**:
We need to analyze the dipole moments of the following molecules: BF3, B2S6, NH3, and NF3.

2. **Analyze BF3**:
- **Structure**: BF3 consists of one boron atom bonded to three fluorine atoms.
- **Hybridization**: The hybridization is sp² (3 bond pairs, 0 lone pairs).
- **Geometry**: The molecular shape is trigonal planar.
- **Dipole Moment**: Due to the symmetrical arrangement of the three fluorine atoms around boron, the dipole moments cancel out, resulting in a net dipole moment of **zero**.

3. **Analyze B2S6**:
- **Structure**: B2S6 consists of two boron atoms and six sulfur atoms.
- **Hybridization**: The hybridization is sp³ (4 bond pairs, 0 lone pairs).
- **Geometry**: The molecular shape is tetrahedral.
- **Dipole Moment**: The symmetrical arrangement leads to a net dipole moment of **zero**.

4. **Analyze NH3**:
- **Structure**: NH3 consists of one nitrogen atom bonded to three hydrogen atoms.
- **Hybridization**: The hybridization is sp³ (3 bond pairs, 1 lone pair).
- **Geometry**: The molecular shape is trigonal pyramidal.
- **Dipole Moment**: The nitrogen-hydrogen bonds create a net dipole moment directed towards the nitrogen due to the electronegativity difference, resulting in a **non-zero dipole moment**.

5. **Analyze NF3**:
- **Structure**: NF3 consists of one nitrogen atom bonded to three fluorine atoms.
- **Hybridization**: The hybridization is also sp³ (3 bond pairs, 1 lone pair).
- **Geometry**: The molecular shape is trigonal pyramidal.
- **Dipole Moment**: The nitrogen-fluorine bonds are highly polar due to the significant electronegativity difference, resulting in a **non-zero dipole moment**.

6. **Compare Dipole Moments**:
- BF3 and B2S6 have dipole moments of **zero**.
- NH3 has a dipole moment due to the nitrogen-hydrogen bonds.
- NF3 has a larger dipole moment than NH3 because the nitrogen-fluorine bonds are more polar than nitrogen-hydrogen bonds.

7. **Conclusion**:
- Among the given molecules, **NF3** has the highest dipole moment due to the highly polar N-F bonds.

### Final Answer:
**NF3 has the highest dipole moment.**