Which of the following substances has dipole moment more than zero ?

Options

A. Water
B. Methane
C. Carbon dioxide
D. Nitrogen

Explanation

To determine which of the following substances has a dipole moment greater than zero, we need to analyze the molecular structure and electronegativity of each substance. Let's go through the options step by step.

### Step 1: Analyze Water (H2O)
- **Structure**: Water has a bent molecular geometry due to the two lone pairs of electrons on the oxygen atom.
- **Electronegativity**: Oxygen is more electronegative than hydrogen, leading to a polar bond.
- **Dipole Moment**: The dipoles from the two O-H bonds do not cancel each other out because of the bent shape, resulting in a net dipole moment.
- **Conclusion**: Water has a dipole moment greater than zero.

### Step 2: Analyze Methane (CH4)
- **Structure**: Methane has a tetrahedral geometry.
- **Electronegativity**: Carbon and hydrogen have a small difference in electronegativity, but the molecule is symmetrical.
- **Dipole Moment**: The dipoles from the four C-H bonds cancel each other out due to the symmetrical tetrahedral shape.
- **Conclusion**: Methane has a dipole moment of zero.

### Step 3: Analyze Carbon Dioxide (CO2)
- **Structure**: Carbon dioxide has a linear structure.
- **Electronegativity**: The electronegativity difference between carbon and oxygen creates polar bonds.
- **Dipole Moment**: However, the two dipoles are equal in magnitude and opposite in direction, leading to cancellation.
- **Conclusion**: Carbon dioxide has a dipole moment of zero.

### Step 4: Analyze Nitrogen (N2)
- **Structure**: Nitrogen is a homonuclear diatomic molecule.
- **Electronegativity**: There is no electronegativity difference since both atoms are nitrogen.
- **Dipole Moment**: As there is no difference in electronegativity, there are no polar bonds.
- **Conclusion**: Nitrogen has a dipole moment of zero.

### Final Conclusion
Among the substances analyzed, only **water (H2O)** has a dipole moment greater than zero.