A) smaller size of B-atom as compared to that of C-atom.
B) stronger or-bond between B and F in \[B{{F}_{3}}\] to that between C and F in \[C{{F}_{4}}.\]
C) significant \[p\pi -p\pi \] 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 \[p\pi -p\pi \] interaction between B and F in \[B{{F}_{4}}\] than that between C and F in \[C{{F}_{4}}.\]
Correct Answer: C
Solution :
[c] In \[B{{F}_{3}}\] there is significant \[p\pi -p\pi \] interaction (back bonding) between unshared p-orbital (having no electron) of boron and the lone pair of electron over fluorine in 2p-orbital. This provides extra stability and thus bond dissociation energy of \[B-F\] in \[B{{F}_{3}}\] is more than \[C-F\] in \[C{{F}_{4}},\] where no such back bonding exist.You need to login to perform this action.
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