Which one of the following pairs is isostructural (i.e., having the same shape and hybridization)?

• A

  $\left[\mathrm{BCl}_3\right.$ and $\left.\mathrm{BrCl}_3\right]$
• B

  $\left[\mathrm{NH}_3\right.$ and $\left.\mathrm{NO}_3^{-}\right]$
• C

  $\left[\mathrm{NF}_3\right.$ and $\left.\mathrm{BF}_3\right]$
• Correct answer
  D

  $\left[\mathrm{BF}_4^{-}\right.$and $\left.\mathrm{NH}_4^{+}\right]$

Solution

If number of bond pairs and lone pairs are same for the given pairs, they are isostructural. (a)
(b)
(c)
(d)
Thus, $\mathrm{BF}_4^{-}$and $\mathrm{NH}_4^{+}$are isostructural.

Hence, the correct answer is option: 'D'.