Question

Which of the following reactions does not take place? ${BF3 + F^{-} ->BF4^{-}}$ $\quad\quad\quad\quad\quad\quad\quad\quad\ldots\left(I\right)$ ${BF3 + 3F^{-} ->BF6^{3-}}$ $\quad\quad\quad\quad\quad\quad\quad\ldots\left(II\right)$ ${AlF3 + 3F^{-} ->AlF6^{3-}}$ $\quad\quad\quad\quad\quad\quad\ldots\left(III\right)$

• A. Only (I)
• B. Only (II)
• C. Only (III)
• D. Only (I) and (III)

Answer 1

Answer: (B)

Only (II)

Answer 2

BF forms complex halides of the type [BF] in which B atom has C.N. 4, it cannot extend its C.N. beyond 4 due to the nonavailability of d-orbitals in its configuration. Hence, BF ion (spd hybridisation) is not formed. On the other hand, Al can extend its C.N. beyond 4 due to the availability of d-orbitals in its configuration.