Question

Which of the following Lewis acid – base interactions are associated with the further involvement of d-orbitals?

i) $Sb{F}_5+HF\to H^{+}[Sb{F}_6{]}^{-}$
ii) $N{H}_3+B{F}_3\to H_{3}NB{F}_3$
iii) $AlC{l}_3+C{l}^{-}\to AlC{l}_4^{-}$
iv) $S{F}_4+F^{-}\to [S{F}_5{]}^{-}$

• A. (i) and (ii)
• B. (i) and (iv)
• C. (ii) and(iii)
• D. (i) and (iii)

Answer 1

The correct option is B (i) and (iv)

Both $Sb{F}_5$ and $S{F}_4$ have all the p orbitals ocuppied. Hence they involve vacant d-orbitals to form $[Sb{F}_6{]}^{-}$ and
$[S{F}_5{]}^{-}$.

$H_{3}NB{F}_3$ here,the lone pair of N is donated to vacant p orbital of B

$AlC{l}_4^{-}$ here, the lone pair of Cl is donated to vacant p orbital of Al
Hence (i) and (iv) are correct