Solution:
In BF3, boron atom has vacant 2pz A.O. and fluorine atom has electron pair in 2p A.O. So maximum overlapping is possible between vacant 2pz A.O. of boron and fully filled 2p A.O. of fluorine due to similar size of A.O.s.
Maximum back bonding exists in
In BF3, boron atom has vacant 2pz A.O. and fluorine atom has electron pair in 2p A.O. So maximum overlapping is possible between vacant 2pz A.O. of boron and fully filled 2p A.O. of fluorine due to similar size of A.O.s.