Question

Which of the following has a trigonal planar shape?

• A. $I{F}_3$
• B. $PC{l}_3$
• C. $N{H}_3$
• D. $B{F}_3$

Answer 1

The correct option is D $B{F}_3$

$I{F}_3$ molecule has 3 bond pairs and 2 lone pairs. So, its steric number is 5 and its hybridisation is $s{p}^{3}d$. Hence, the geometry of $I{F}_3$ molecule is trigonal bipyramidal and has a distorted T-shape.
$PC{l}_3$ molecule has 3 bond pairs and 1 lone pair. So, its steric number is 4 and its hybridisation is $s{p}^3$. Hence, the geometry of $PC{l}_3$ molecule is tetrahedral and the shape is pyramidal.

$N{H}_3$ molecule has 3 bond pairs and 1 lone pair. So, its steric number is 4 and its hybridisation is $s{p}^3$. Hence, the geometry of $N{H}_3$ molecule is tetrahedral and the shape is pyramidal.

$B{F}_3$ molecule has 3 bond pairs and no lone pairs. So, its steric number is 3 and its hybridisation is $s{p}^2$. Hence, the geometry and the shape of $B{F}_3$ molecule is trigonal planar.