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. smallar size of B-atom as compared to that of
C-atom
B. stronger `sigma`-bond between B and F in `BF_(3)`as
compared to that between C and F in `CF_(4)`
C. significant `ppi-ppi` 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 `ppi-ppi` interaction between B
and F in `BF_(3)` than 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 , formaing
` pi`-bond . Thus , B-F bond length becomes shorter.
Hence, bond is stronger and dissociation energy
is higher .