Question

For $B{F}_3$ molecule, which of the following is true?

• A. $B$ atom is $s{p}^2$ hybridized
• B. There is a $p\pi —p\pi$ back bonding in this molecule
• C. Observed $B—F$ bond length is found to be less than the expected bond length
• D. All of these

Answer 1

The correct option is D All of these

a) In $B{F}_3$, the central $B$ has three bond-pairs. Hence, it is $s{p}^2$ hybridised and has trigonal planner shape .

b) In $B{F}_3$, there exists back bonding between $F$ atoms and the central $B$ as $F$ can donate lone pair of electrons to the vacant $2p$ orbitals of the central atom $\left(B\right)$.

c) The $B-F$ bond length in $B{F}_3$ is shorter than the expected $B-F$ bond length due to back bonding. Because of back bonding there is a partial double bond character and all bond lenghts are the same.