Which does not have zero value of dipole moment?

Options

A. `[Ni(CN)_4 ]^(2-)`
B. `CHCl_3`
C. `CO_2`
D. `NH_(3)`

Explanation

To determine which of the given molecules does not have a zero value of dipole moment, we will analyze each option provided in the question. The dipole moment is a measure of the polarity of a molecule, and it is influenced by the shape of the molecule and the electronegativity of the atoms involved.

### Step-by-Step Solution:

1. **Understanding Dipole Moment**:
- The dipole moment is a vector quantity that measures the separation of positive and negative charges in a molecule. It is calculated as the product of the charge and the distance between the charges.

2. **Analyzing NH3 (Ammonia)**:
- **Structure**: NH3 has a trigonal pyramidal shape due to one lone pair on nitrogen.
- **Electronegativity**: Nitrogen is more electronegative than hydrogen, leading to a dipole moment directed from the hydrogen atoms towards the nitrogen atom.
- **Conclusion**: NH3 has a non-zero dipole moment because the dipoles do not cancel out.

3. **Analyzing CO2 (Carbon Dioxide)**:
- **Structure**: CO2 has a linear structure.
- **Electronegativity**: Oxygen is more electronegative than carbon, creating dipoles towards each oxygen atom.
- **Conclusion**: The dipoles in CO2 are equal in magnitude but opposite in direction, resulting in a net dipole moment of zero. Thus, CO2 has a zero dipole moment.

4. **Analyzing CHCl3 (Chloroform)**:
- **Structure**: CHCl3 has a tetrahedral shape.
- **Electronegativity**: Chlorine is more electronegative than carbon, while hydrogen is less electronegative. The dipoles from C-Cl bonds do not cancel out due to the presence of three chlorine atoms.
- **Conclusion**: CHCl3 has a non-zero dipole moment because the dipoles do not cancel out.

5. **Analyzing [Ni(CN)4]2- (Nickel Complex)**:
- **Structure**: This complex has a square planar geometry.
- **Electronegativity**: The cyanide ions are strong ligands and will create dipoles. However, due to the symmetry of the square planar structure, the dipoles will cancel each other out.
- **Conclusion**: [Ni(CN)4]2- has a zero dipole moment.

### Final Conclusion:
From the analysis, the molecule that does not have a zero value of dipole moment is **NH3 (Ammonia)** and **CHCl3 (Chloroform)**. The other two, **CO2 (Carbon Dioxide)** and **[Ni(CN)4]2- (Nickel Complex)**, have zero dipole moments.