Which of the following molecules has a non-zero dipole moment?

Solution

1. ${\text{BF}}_3$ is trigonal planar with a dipole moment of zero.
2. ${\text{SF}}_6$ is octahedral and symmetric with a dipole moment of zero.
3. ${\text{CO}}_2$ is linear with a dipole moment of zero.
4. ${\text{SO}}_2$ has a bent geometry due to alone pair on sulfur, resulting in a non-zero dipole moment.
5. Hence the answer is (C).