Which of the following is a non-polar solvent?

Which molecule has the maximum dipole moment $\mu$? (where $X = -NO_2$)

If $Q$ is the magnitude of charge and $r$ is the distance between the centres of positive and negative charges,then the dipole moment $(\mu)$ is given by:

Which one of the following has the highest dipole moment?
$(i)$ $CH_2Cl_2$
$(ii)$ $CHCl_3$
$(iii)$ $CCl_4$

Dipole moment of $HCl = 1.03 \ D$ and $HI = 0.38 \ D$. Bond length of $HCl = 1.3 \ \mathring{A}$ and $HI = 1.6 \ \mathring{A}$. The ratio of the fraction of electric charge,$\delta$,existing on each atom in $HCl$ and $HI$ is:

Which one has minimum (nearly zero) dipole moment?