In compounds of type `ECI_(3)`, where `E=BP`, As or `B`, the angles `CI-E-CI` for different `E` are in the order

Options

A. BgtP=As=Bi
B. BgtP gt AsgtBi
C. B lt P =As= Bi
D. B lt P lt As lt Bi

Answer

B

Explanation

In `BCl_3` , the state of hybridisation , H=1 (3+3+0-0) = 3 i.e. `sp^2`
So the bond angle is `120^@`
The state of hybridisation in case of P, As and Bi is `sp^3` hybridisation and due to the presence of a lone pair on the central atom the bond angle is less than normal tetrahedral angle of `109^@28'` i.e. bond angle lt `109^@ 28'` . Since the central atom (P,As,Bi) belong to the same group, the bond angle of `ECl_3` decreases as we go down the group, i.e., from P to As to Bi, thus the correct order of bond angle is `BCl_3 gt PCl_3 gt AsCl_3 gt BiCl_3`