JEE Main 2008 — Chemical Bonding And Molecular Structure Question with Solution
From: AIEEE 2008
Question
The bond dissociation energy of B - F in BF3 is 646 kJ mol-1 whereas 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 is
Choose an option
Show full solutionCorrect option: B
Correct answer
Bsignificant interaction between B and F in BF3 whereas there is no possibility of such interaction between C and F in CF4
Step-by-step explanation
In BF3, B is sp2
hybridised and by Back Bonding method strong p-p bond is created between filled p-orbital of F and vacant p-orbital of
B which leads to shortening of B–F bond length which results in higher bond dissociation energy of
the B–F bond. However in CF4, C does not have any vacant
p-orbitals to undergo -bonding.
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