Polarity in a molecule and hence the dipole moment depends primarily on electronegativity of the constituent atoms and shape of a molecule. Which of the following has the highest dipole moment?

The types of hybrid orbitals of nitrogen in $\mathrm{NO}_2^{+}, \mathrm{NO}_3^{-}$and $\mathrm{NH}_4^{+}$ respectively are expected to be

Hydrogen bonds are formed in many compounds e.g., $\mathrm{H}_2 \mathrm{O}, \mathrm{HF}, \mathrm{NH}_3$. The boiling point of such compounds depends to a extent on the strength of hydrogen bond and the number of hydrogen bonds. The correct decreasing order of the boiling points above compounds is

In $\mathrm{PO}_4^{3-}$ ion the formal charge on the oxygen atom of $\mathrm{P}-0$ bond is

In $\mathrm{NO}_3^{-}$ion, the number of bond pairs and lone pairs of electrons on nitrogen atom are