Which one is a polar molecule among the following?

Which of the following is the most polar?

Identify the molecule with the highest dipole moment from the following:

If the bond length and dipole moment of a diatomic molecule are $1.25 \ \mathring{A}$ and $1.0 \ D$ respectively,what is the percent ionic character of the bond?

Which of the following molecules has no dipole moment?

Identify the correct order of average molecular dipole moment for the following species: $PCl_3F_2$, $N_2O_{4(g)}$, and $N_2O_{4(s)}$.