Which of the following reactions does not take place? aligned & BF ₃+ F ⁻ BF ₄⁻ & BF ₃+3 ~F ⁻ BF ₆³⁻ & AlF ₃+3 ~F ⁻ AlF ₆³⁻ aligned

Step-by-step solution

BF ₃ forms complex halides of the type [ BF ₄⁻ ] 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 ₆³⁻ ion (s p^3 d^2 . 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.