JEE Main 2002 — Chemical Bonding And Molecular Structure Question with Solution

Bond angle 109^o 28' means Regular Tetrahedral geometry and hybridization is sp³.

Steric Number (SN) for sp³ hybridization is 4.

In sp³ molecules can have different shapes which is decided by SN number

(1) 4 bond pair in a molecule then angle between bonds 109^o 28^'

(2) 3 bond pair and 1 lone pair in a molecule then angle between bonds 107^o.

(3) 2 bond pair and 2 lone pair in a molecule then angle between bonds 104.5^o

(4) 1 bond pair and 3 lone pair in a molecule then bond angle is undefined as there is only one bond.

(1) In NH₃, 3 Bond pair(BP) +1 lone pair (LP) present so angle between bond 107^o.



(2) BF$${}_4^{-}$$, 4 bond pair present so angle is 109^o 28^'.



(3) In NH$${}_4^{+}$$, 4 bond pair present so angle between bond is 109^o 28^'



(4) BF₃ has sp² hybridization. So bond angle is 120^o.



(5) In NH$${}_2^{-}$$, 2 bond pair and 2 lone pair present, so bond angle is 104.5^o



So, $$NH{}^{+}$$ and BF$${}_4^{-}$$ has bond angle 109^o 28^'.