Which of the following possess a net dipole moment?

If $HCl$ molecule is completely polarized,the expected value of the dipole moment is $6.12 \ D$,but the experimental value of the dipole moment is $1.03 \ D$. Calculate the percentage ionic character.

The standard molar enthalpy of vaporisation $(\Delta_{vap}H^{\circ})$ of $A, B$ and $C$ liquids is $23.3, 41$ and $29 \ kJ \ mol^{-1}$ respectively. The correct order of dipole-dipole attractive forces in these liquids is

Pick out the molecule which has zero dipole moment.

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:

The cyanide ion $(CN^{-})$ and $N_2$ are isoelectronic. However,in contrast to $CN^{-}$,the $N_2$ molecule is chemically inert due to: