Looking for classes? Ksquare Career Institute, Bengaluru →
In which of the following molecules does the central atom not have $sp^3$ hybridization?
A
$CH_4$
B
$SF_4$
C
$BF_4^-$
D
$NH_4^+$
Detailed Solution
Count σ bonds + lone pairs on the central atom.
$CH_4$: 4 bond pairs + 0 lone pairs = 4, so $sp^3$.
$BF_4^-$: 4 bond pairs + 0 lone pairs = 4, so $sp^3$.
$NH_4^+$: 4 bond pairs + 0 lone pairs = 4, so $sp^3$.
$SF_4$: sulphur has 6 valence electrons; 4 are used in bonds and 2 remain as one lone pair. 4 bond pairs + 1 lone pair = 5, so $sp^3d$ (see-saw shape).
Hence the central atom is not $sp^3$ hybridised in $SF_4$.
$CH_4$: 4 bond pairs + 0 lone pairs = 4, so $sp^3$.
$BF_4^-$: 4 bond pairs + 0 lone pairs = 4, so $sp^3$.
$NH_4^+$: 4 bond pairs + 0 lone pairs = 4, so $sp^3$.
$SF_4$: sulphur has 6 valence electrons; 4 are used in bonds and 2 remain as one lone pair. 4 bond pairs + 1 lone pair = 5, so $sp^3d$ (see-saw shape).
Hence the central atom is not $sp^3$ hybridised in $SF_4$.