Which of the following posses net dipole moment ?

Options

A. `SO_(2)`
B. `BF_(3)`
C. `BeCl_(2)`
D. `CO_(2)`

Explanation

To determine which of the given molecules possesses a net dipole moment, we will analyze each option step by step.

### Step-by-Step Solution:

1. **Understanding Dipole Moment**:
- A dipole moment occurs in a molecule when there is an uneven distribution of electron density, leading to a positive and a negative end (pole). A molecule has a net dipole moment if the vector sum of all individual dipole moments does not equal zero.

2. **Analyzing Option A: SO2 (Sulfur Dioxide)**:
- **Structure**: SO2 has a sulfur atom (S) as the central atom bonded to two oxygen atoms (O) with one lone pair on sulfur.
- **Steric Number**: The steric number is calculated as the number of sigma bonds plus lone pairs. SO2 has 2 sigma bonds and 1 lone pair, giving a steric number of 3.
- **Hybridization**: The hybridization of sulfur in SO2 is sp².
- **Geometry**: The geometry is trigonal planar, but due to the lone pair, the shape is bent (angular).
- **Dipole Moments**: The dipole moments from the S=O bonds point towards the oxygen atoms, and the lone pair also contributes to the dipole moment. The overall dipole moment does not cancel out, resulting in a net dipole moment.
- **Conclusion**: SO2 has a net dipole moment.

3. **Analyzing Option B: BF3 (Boron Trifluoride)**:
- **Structure**: BF3 has a boron atom at the center bonded to three fluorine atoms.
- **Steric Number**: The steric number is 3 (3 sigma bonds, 0 lone pairs).
- **Hybridization**: The hybridization of boron in BF3 is sp².
- **Geometry**: The geometry is trigonal planar.
- **Dipole Moments**: The dipole moments from each B-F bond point towards the fluorine atoms. Due to symmetry, these dipole moments cancel each other out.
- **Conclusion**: BF3 has no net dipole moment.

4. **Analyzing Option C: BeCl2 (Beryllium Chloride)**:
- **Structure**: BeCl2 has a beryllium atom at the center bonded to two chlorine atoms.
- **Steric Number**: The steric number is 2 (2 sigma bonds, 0 lone pairs).
- **Hybridization**: The hybridization of beryllium in BeCl2 is sp.
- **Geometry**: The geometry is linear.
- **Dipole Moments**: The dipole moments from the Be-Cl bonds point towards the chlorine atoms. Due to symmetry, these dipole moments cancel each other out.
- **Conclusion**: BeCl2 has no net dipole moment.

5. **Analyzing Option D: CO2 (Carbon Dioxide)**:
- **Structure**: CO2 has a carbon atom at the center bonded to two oxygen atoms.
- **Steric Number**: The steric number is 2 (2 sigma bonds, 0 lone pairs).
- **Hybridization**: The hybridization of carbon in CO2 is sp.
- **Geometry**: The geometry is linear.
- **Dipole Moments**: The dipole moments from the C=O bonds point towards the oxygen atoms. Due to symmetry, these dipole moments cancel each other out.
- **Conclusion**: CO2 has no net dipole moment.

### Final Conclusion:
Among the given options, only **SO2** possesses a net dipole moment.