Chemistry - Complete Pblock- Question with Solution | TestHub

(i)$\text{N}-\text{O}$bond is shorter than$\text{N}-\text{OH}$bond in${\text{HNO}}_{\text{3}}$molecule. It can be understood with the help of resonating structures of${\text{HNO}}_{\text{3}}$molecule.

As we can see from the resonating structures, there is double bond character between$\text{N}-\text{O}$bonds but there is always single bond character between$\text{N}-\text{OH}$bond. This is because of no pi-bonding occurring between nitrogen and oxygen of$-\text{OH}$group.

Double bond is shorter than single bond. So$\text{N}-\text{O}$bond is shorter than$\text{N}-\text{OH}$bond in${\text{HNO}}_3$molecule.

(ii) There are two bonds in${\text{PCl}}_{\text{5}}$. One is equatorial and other is axial, because of the repulsion factor one is longer and the other shorter.

(iii)$\text{I}-\text{Cl}$bond is weaker than$\text{I}-\text{I}$bond