Which of the following molecules has zero dipole moment?

Among $H_2S$, $H_2O$, $NF_3$, $NH_3$ and $CHCl_3$, identify the molecule $(X)$ with the lowest dipole moment value. The number of lone pairs of electrons present on the central atom of the molecule $(X)$ is:

If $H-X$ bond length is $2 \ \mathring{A}$ and $H-X$ has dipole moment $5.12 \times 10^{-30} \ C \cdot m$,the $\%$ of covalent character of the molecule is ............. $\%$

Which one of the following has the highest dipole moment?

Which of the following bonds has the highest polarity?

What is the physical shape and dipole moment of $H_2S$?