Question

Identify the sets containing isostructural molecules from the following 

I. \(\text{SiF}_4\), \(\text{SF}_4\)
II. \(\text{IO}_3^-\), \(\text{XeO}_3\)
III. \(\text{BH}_4^-\), \(\text{NH}_4^+\)
IV, \(\text{PF}_6^-\), \(\text{SF}_6\)
The correct option is

• A. 1.II, III, IV only
• B. 2.I, II, III only
• C. 3.III, IV only
• D. 4.II, IV only

Hint:

Isostructural molecules have the same molecular geometry and bond angles, though the atoms or ions involved may differ.

Answer 1

The Correct Option is A

- \(\text{SiF}_4\) and \(\text{SF}_4\) are not isostructural because the central atoms in these molecules have different numbers of valence electrons and bond angles.
- \(\text{IO}_3^-\) and \(\text{XeO}_3\) are isostructural as both have a similar arrangement of atoms with the central atom bonded to three oxygen atoms in a trigonal pyramidal geometry.
- \(\text{BF}_4^-\) and \(\text{NH}_4^+\) are isostructural because both have a tetrahedral geometry.
- \(\text{PF}_6^-\) and \(\text{SF}_6\) are isostructural as both are octahedral in shape.
Thus, the correct answer is II, III, IV only.