Question

Structure anions of acids, $HNO_{3}, H_{3}PO_{4}$ and $H_{2}SO_{4}$ are, respectively

• A. tetrahedral, tetrahedral and trigonal bipyramidal
• B. angular, tetrahedral and trigonal bipyramidal
• C. tetrahedral, tetrahedral and angular
• D. planar, tetrahedral and tetrahedral

Answer 1

Answer: (D)

planar, tetrahedral and tetrahedral

Answer 2

Anions of the acids $HNO_{3}, H_{3}PO_{4}$ and $H_{2}SO_{4}$ are $NO^{-}_{3}, PO^{3-}_{4}$ and $SO^{2-}_{4}$ respectively
Their structures can be explained as follows:
$NO^{-}_{3}$ has planar structure It has nitrogen as a central atom without lone pair, whidi is bonded to three oxygen atoms. Its hybridisation can be predicted by $\frac{1}{2}[V+M-C+A]$
Where $V$ = number of valence electrons
$M$ = number of monovalent ion
$C$= cationic charge
$A$ - anionic charge
$\therefore$ Hybridisation $=\frac{1}{2}[5+0-0+1]=3$

$PO^{3-}_{4}$ has tetrahedral structure. It has phosphorus as a central atom without lone pair which is bonded to four oxygen atoms. Its hybridisation can be predicted as $\frac{1}{2}[5+0-0+3]=3$

$SO^{2-}_{4}$ has tetrahedral structure. It has phosphorus as a central atom without lone pair which is bonded to four oxygen atoms. Its hybridisation can be predicted as
$\frac{1}{2}[6+0-0+2]=4$