Which of the following compounds has a zero dipole moment?

Experiment shows that $H_2O$ has a dipole moment while $CO_2$ does not. Point out the structures which best illustrate these facts.

Which of the following is polar?

Which set contains molecules with $\mu = 0$?

$A$ covalent molecule $XY$ is found to have a dipole moment of $1.5 \times 10^{-29} \ C \cdot m$ and a bond length of $150 \ pm$. The percent ionic character of the bond will be (in $\%$)

Which one of the following molecules has the maximum dipole moment?