Question

Which of following statement is correct ? .
A. The bond angle of `NCI_(3)` is greater than that of `NH_(3)`
B. The bond angle of `PH_(3)` is greater than that of `PF_(5)`
C. `CIO_(3)^(Θ)` and `SO_(3)^(2-)` are isostructural
D. It is not necessary that in Tbp structure the lone pairs always would occupy the equatorial positions .

Answer 1

Correct Answer - C
In `NCI_(3),CI` is more `EN` thus bond pairs are pushed near Therefore bond angle of `NCI_(3) lt NH_(3)`
(b) In `PF_(5) F` is more `EN` Therefore Bond angle of `PF_(5) lt PH_(3)`
(c ) Hybridisation of `CIO_(3)^(Theta) = (1)/(2) (7+0+1) =4 = sp^(3)`
Hybridisation of `SO_(3)^(2-) = (1)/(2) (6 +0 +2) = 4 = sp^(3)`
Therefore `CIO_(3)^(Theta)` and `SO_(3)^(2-)` are isostructural and in both cases d-orbitals participate in (p pi -d pi) bonding with O-atom
In Tbp structure the lp s always occupy the equatorial position becasue angle between equational bonds is `120^(@)` and there is less repulsion between lp-lp thus providing a greater stability to the molecule .