The study of diple
moment of a molecule is useful to explain the
shape of a molecule and also to predict a
The net dipole moment of a polyatomic
molecule is the resltant of the different bond
moments present in that molecule . The values
are generalluy expressed in Debye or in the S.I.
units in terms of Coulomb meter (C m)
Which our of the following will have maximum
dipole moment ?

Options

A. `NF_(3)`
B. `NCl_(3)`
C. `NBr_(3)`
D. `NH_(3)`

Explanation

To determine which of the given molecules has the maximum dipole moment, we need to analyze the molecular structures and the electronegativity of the atoms involved. The molecules we are considering are NF3 (Nitrogen trifluoride), NCl3 (Nitrogen trichloride), NBr3 (Nitrogen tribromide), and NH3 (Ammonia).

### Step-by-Step Solution:

1. **Understanding Dipole Moment**:
- The dipole moment (\( \mu \)) is a vector quantity that depends on the difference in electronegativity between the bonded atoms and the geometry of the molecule. It points from the less electronegative atom to the more electronegative atom.

2. **Analyzing Each Molecule**:
- **NF3**:
- Nitrogen (N) has an electronegativity of about 3.0, and Fluorine (F) has an electronegativity of about 4.0.
- The dipole moments from the N-F bonds point towards the fluorine atoms, but due to the trigonal pyramidal shape, the dipoles partially cancel each other out.

- **NCl3**:
- Chlorine (Cl) has an electronegativity of about 3.0, similar to nitrogen.
- The dipole moments from the N-Cl bonds also point towards the chlorine atoms, but they will also partially cancel due to the geometry of the molecule.

- **NBr3**:
- Bromine (Br) has an electronegativity of about 2.8, which is less than that of nitrogen.
- The dipole moments from the N-Br bonds will point towards nitrogen, and since the electronegativity difference is small, the overall dipole moment will be less than that of NF3 and NCl3.

- **NH3**:
- Hydrogen (H) has an electronegativity of about 2.1, which is significantly less than nitrogen.
- The dipole moments from the N-H bonds point towards nitrogen, and since there are three N-H bonds, the dipoles add up constructively, resulting in a significant net dipole moment.

3. **Comparing the Dipole Moments**:
- NF3 and NCl3 have dipole moments that partially cancel due to their molecular shapes.
- NBr3 has a lesser dipole moment due to the lower electronegativity of bromine.
- NH3 has a strong net dipole moment due to the significant difference in electronegativity between nitrogen and hydrogen and the additive nature of the dipoles.

4. **Conclusion**:
- Among the given molecules, **NH3 (Ammonia)** has the maximum dipole moment.

### Final Answer:
The molecule with the maximum dipole moment is **NH3 (Ammonia)**.