Question

Maximum `p pi-p pi` back bonding exists in
A. `BCl_(3)`
B. `BI_(3)`
C. `BBr_(3)`
D. `BF_(3)`

Answer 1

Correct Answer - D
In `BF_(3)`, boron atom has vacant `2p_(z)A.O.` and flurine atom has electron pair in `2 p A.O.` So maximum overlapping is possible between vacant `2p_(z) A.O.` of boron and fully filled `2p A.O.` of fluorine due to similar size of `A.O.`s.