Positive dipole moment is present in

Which of the following is polar?

Which of the following dissolves in ionic solvents?

The dipole-dipole interaction energy between polar molecules in the solid state will be proportional to ...... [if $r$ denotes the distance between polar molecules]

$A$ neutral molecule $XF_3$ has a zero dipole moment. The element $X$ is most likely

Which one has minimum (nearly zero) dipole moment?