Q. The bond dissociation energy of $B - F$ in $B F_{3}$ is $646 k J m o l^{- 1}$ whereas that of $C - F$ in $C F_{4}$ is $515 k J m o l^{- 1}$ . The correct reason for higher $B - F$ bond dissociation energy as compared to that of $C - F$ is :

4116 208 AIEEEAIEEE 2009 Report Error

A

smaller size of B-atom as compared to that of C- atom

B

stronger $σ$ bond between B and F in 3 BF as compared to that between C and F in $C F_{4}$

C

significant $p π - p π$ interaction between $B$ and $F$ in $B F_{3}$ whereas there is no possibility of such interaction between C and F in $C F_{4}$

D

lower degree of $p π - p π$ interaction between $B$ and $F$ in $B F_{3}$ than that between C and F in $C F_{4}$

Solution:

option itself is the reason