The bond dissociation energy of `B-F` in `BF_(3)` is `"646 kJ mol"^(-1)` whereas that of `C-F` in `CF_(4)` is `"515 kJ mol"^(-1)`. The correct reason for higher `B-F` bond dissociation energy as compared to that of `C-F` is

Options

A. smaller size of B-atom as compared to that of C-atom
B. stronger `sigam`-bond between B and F is `BF_(3) ` as
compared to that between C and F in ` CF_(4)`
C. significant `p pi -p pi` interaction between B and F
in ` BF_(3)` whereas there is no possibility of such interaction between C and F in ` CF_(4)`
D. lower degree of `p pi - p pi` interaction between B and F
in ` BF_(3)` than that between C and F in ` CF_(4)`

Answer

c

Explanation

The empty ` 2P_(z)` orbitals of B which is not involved in
the hybridisation can accept an electron pair from a
full ` 2P_(z)` orbitals of any F-atom , forming ` pi`-bond (bond length becomes shorter ).