Question

Determine the geometry of each of the following molecules and hybridization about the central atom in:
(i) $Be{F}_2\left(g\right)$
(ii) $Al{H}_3$
(iii) $CH\equiv CH$

• A. (i) $sp$, linear (ii) $s{p}^2$, trigonal planar (iii) $s{p}^2$, planar
• B. (i) $s{p}^2$, planar (ii) $sp$, linear (iii) $s{p}^2$, planar
• C. (i) $sp$, trigonal planar (ii) $s{p}^2$, linear (iii) $s{p}^2$, planar
• D. (i) $sp$, linear (ii) $s{p}^2$, trigonal planar (iii) $sp$, linear

Answer 1

The correct option is D (i) $sp$, linear (ii) $s{p}^2$, trigonal planar (iii) $sp$, linear

$H=\frac{1}{2}[V+M-C+A]$
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 options:-
A) $Be{F}_2$
$H=\frac{1}{2}[2+2]=2$ $\Rightarrow s{p}^2$ hybridized state
It is trigonal planar in shape.
B) $Al{H}_3$
$H=\frac{1}{2}[3+3]=3$ $\Rightarrow s{p}^2$ hybridized state
It is trigonal planar in shape.
C) $C_2{H}_2$
Since it is an alkyne, it is $sp$ hybridized and linear in shape.