Among H_2 S, H_2 O, NF_3, NH_3 and CHCl_3, identify the molecule ( X ) with lowest dipole moment value. The number of lone pairs of electrons present…

Among $\displaystyle \mathrm{H}_2 \mathrm{~S}, \mathrm{H}_2 \mathrm{O}, \mathrm{NF}_3, \mathrm{NH}_3$ and $\displaystyle \mathrm{CHCl}_3$, identify the molecule $\displaystyle (\mathrm{X})$ with lowest dipole moment value. The number of lone pairs of electrons present on the central atom of the molecule $\displaystyle (\mathrm{X})$ is :