Question
The total number of molecules with zero dipole moment among $\mathrm{CH}_4, \mathrm{BF}_3, \mathrm{H}_2 \mathrm{O}, \mathrm{HF}, \mathrm{NH}_3, \mathrm{CO}_2$ and $\mathrm{SO}_2$ is ________.
Correct Answer
3
The total number of molecules with zero dipole moment among $\mathrm{CH}_4, \mathrm{BF}_3, \mathrm{H}_2 \mathrm{O}, \mathrm{HF}, \mathrm{NH}_3, \mathrm{CO}_2$ and $\mathrm{SO}_2$ is ________.