The bond dissociation energy of B – F in BF₃ is 646 kJ mol^–1. where as that of C – F in CF₄ is 515 kJ mol^–1. The correct reason for higher B – F bond dissociation energy as compared to that of C – F bond is

Moderate

A

stronger σ bond between B and F in BF₃ as compared to that between C and F in CF₄
B

Significant pπ - pπ interaction between B and F in BF₃ whereas there is no possibility of such interaction between C and F in CF₄
C

Lower degree of pπ - pπ interaction between B and F in BF₃ than that between C and F in CF₄
D

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

Solution

$B - F\,bond\,order = \frac{{2 + 1 + 1}}{3} = \frac{4}{3} = 1.33$
$\large B.O\; \propto \;\frac{1}{{B.L}}$
$\large B.O\; \propto \;B.E$
In BF₃ due to back π-bonding the bond order is more and hence bond dissociation energy is more [646KJ/mole]
Where as in case of CF₄ there is no such back π-bond formation, hence the C - F bond order is less so bond dissociation energy for C - F bond is low [515KJ/mole]

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