Question

Which of the following are iso-structural species?

• A. $NH_{4}^{+}$ and $NH_{2}^{-}$
• B. $CH_{3}^{-}$ and $CH_{3}^{+}$
• C. $SO_{4}^{2-},PO_{4}^{3-}$ and $[BF_{4}^{-}]$
• D. $NH_{4}^{+}$ and $N{{H}_{3}}$

Answer 1

Answer: (C)

$SO_{4}^{2-},PO_{4}^{3-}$ and $[BF_{4}^{-}]$

Answer 2

Hybridisation can be calculated by calculating the no of valence electron and dividing it by 8 . In $SO _{4}{ }^{2-}=$ Total no. of $e ^{-}$ $=6+(6 \times 4)+2=32$ So, no. of hybrid orbitals $=\frac{32}{8}=4$ $\therefore sp ^{3}$ hybridization. Similarly, for $PO _{4}{ }^{3-}$; no. of hybrid orbitals $=\frac{5+24+3}{8}$ $=\frac{32}{8}=4$ Hybridisation $= sp ^{3}$ Similarly, for $BF _{4}^{-}$, it is $sp ^{3}$.