Question

Which of the following two species have the same shape?
(I) $N{I}_3$
(II) ${I_3}^{-}$
(III) ${S{O}_3}^{2-}$
(IV) ${N{O}_3}^{-}$

• A. I and II
• B. II and III
• C. III and I
• D. I and IV

Answer 1

Answer: (C)

III and I

$H=\frac{1}{2}[V+M-C+A]$
where,
H= Number of orbitals involved in hybridization
V=Valence electrons of central atom
M- Number of monovalent atoms linked to central atom
C= Charge of cation
A= Charge of anion
Consider the hybridization and shape of the given species:-
i) $N{I}_3$
$H=\frac{1}{2}[5+3]=4$ $\Rightarrow s{p}^3$ hybridized state
It is trigonal pyramidal in shape.
ii) ${I_3}^{-}$
$H=\frac{1}{2}[7+2+1]=5$ $\Rightarrow s{p}^{3}d$ hybridized state
It is linear in shape.
iii) ${S{O}_3}^{2-}$
$H=\frac{1}{2}[6+2]=4$ $\Rightarrow s{p}^3$ hybridized state
It is trigonal pyramidal in shape.
iv) ${N{O}_3}^{-}$
$H=\frac{1}{2}[5+1]=3$ $\Rightarrow s{p}^2$ hybridized state
It is trigonal planar in shape.
Hence, option C is the right answer.