a) Discuss the significance/applications of dipole moment.
b) Represent diagrammatically the bond moments and the resultant dipole moment in `CO_(2), NF_(3)` and `CHCl_(3)`

Explanation

### Step-by-Step Text Solution

#### Part a: Significance/Applications of Dipole Moment

1. **Determination of Polarity**:
- The dipole moment (μ) helps in determining whether a molecule is polar or non-polar. A non-zero dipole moment indicates that the molecule is polar, while a zero dipole moment indicates that it is non-polar.

2. **Ionic Character**:
- The dipole moment can be used to calculate the percentage of ionic character in a bond. This is given by the formula:
\[ \text{Percentage Ionic Character} = \left( \frac{\mu_{\text{observed}}}{\mu_{\text{ionic}}} \right) \times 100 \]
- Here, μ_observed is the measured dipole moment, and μ_ionic is the dipole moment expected for a completely ionic bond.

3. **Symmetry of Molecules**:
- Dipole moments can indicate the symmetry of molecules. For example, a symmetrical molecule like CCl₄ has a dipole moment of zero, suggesting that it is non-polar.

4. **Cis-Trans Isomerism**:
- The dipole moment can help differentiate between cis and trans isomers. Generally, cis isomers have a higher dipole moment than trans isomers due to the arrangement of functional groups.

5. **Ortho, Meta, and Para Isomers**:
- Dipole moments can also provide information about the relative positions of substituents in aromatic compounds, such as ortho, meta, and para isomers.

#### Part b: Diagrammatic Representation of Dipole Moments

1. **CO₂ (Carbon Dioxide)**:
- CO₂ has a linear structure. The dipole moments from each C=O bond are equal in magnitude but opposite in direction, resulting in a net dipole moment of zero.
- **Diagram**:
```
O ← C → O
(Dipole moments cancel out)
```

2. **NF₃ (Nitrogen Trifluoride)**:
- NF₃ has a trigonal pyramidal shape due to the presence of a lone pair on nitrogen. The dipole moments from each N-F bond point towards the fluorine atoms.
- **Diagram**:
```
F
|
F - N (lone pair)
|
F
(Resultant dipole moment points upwards)
```

3. **CHCl₃ (Chloroform)**:
- CHCl₃ has a tetrahedral structure. The dipole moments from the C-Cl bonds point towards the chlorine atoms, while the C-H bond points towards the hydrogen atom.
- **Diagram**:
```
Cl
|
Cl - C - H
|
Cl
(Resultant dipole moment points towards Cl)
```