What is dipole moment ? How does it affect the polarity of the molecule ? Which of the following molecules do you expect to be polar?
`CO, C Cl_(4), H_(2)O, BF_(3), NH_(3) and CO_(2)`

Explanation

### Step-by-Step Solution:

1. **Definition of Dipole Moment**:
- The dipole moment is a measure of the polarity of a chemical bond between two atoms in a molecule. It is a vector quantity, which means it has both magnitude and direction.

2. **Understanding Polarity**:
- Polarity in a molecule arises when there is an uneven distribution of electron density between the atoms involved in a bond. This results in one atom being partially positive and the other being partially negative.
- If the dipole moment of a molecule is equal to zero, the molecule is considered non-polar. Conversely, if the dipole moment is not equal to zero, the molecule is polar.
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