Question

Maximum bond angle at nitrogen is present in which of the following ?

<!--td {border: 1px solid #ccc;}br {mso-data-placement:same-cell;}--> AIPMT – 2015

Answer 1

There are many factors which affect the bond angle in different ways and are given below
(i) Repulsion present between the atoms or groups attached to the central atoms can increase or decrease the bond angle. Larger the repulsion, the greater will be the bond angle. More the attractions, lesser the bond angle.
(ii) When the hybridization is considered, the bond angle increases with the increase in the s-character of the s-hybrid bond. For example,
(a) A molecule with a central atom in $s{p}^3$ has $25\%$ s-character and thus has a lesser bond angle ${109}^{\circ }28\text{'}$.
(b) A molecule with a central atom in $s{p}^2$ has $33.33\%$ s-character, and thus have a bond angle a bit greater than $s{p}^3$, that is ${120}^{\circ }.$
(c) A molecule with a central atom in $sp$ has the maximum s-character as $50\%$ and thus have maximum
bond angle as ${180}^{\circ }$

$N{O}_2^{+}:\text{sp hybridisation (bond angle}={180}^{\circ })$

$\underset{bondangle\uparrow }{\overset{N{O}_2^{-}<N{O}_3^{-}<N{O}_2<N{O}_2^{+}}{\to }}$