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# The bond dissociation energy of $B-F$ in $BF_3$ in 646KJ$mol^{-1}$ whereas that of C-F in $CF_4$ is 515KJ$mol^{-1}$. The correct reason for higher B-F bond dissociation energy as compared to that of C-F is

$\begin{array}{1 1}(a)\;\text{Stronger }\sigma\text{ bond between B and F in }BF_3\text{ as compared to that between C and F in }CF_4\\(b)\;\text{Significant }p\pi-p\pi\text{ interaction between B and F in }BF_3\text{ whereas there is no possibility of such interaction between C and F in }CF_4\\(c)\;\text{Smaller size of B-atom as compared to that of C-atom}\\(d)\;\text{Lower degree of }p\pi-p\pi\text{ interaction between B and F in }BF_3\text{ than that between C and F in }CF_4\end{array}$

Can you answer this question?

In $BF_3$ there is a significant $P\pi-P\pi$ interaction between B and F and such kind of interaction is not possible in case of $CF_4$
Hence (b) is the correct answer.
answered Mar 10, 2014