Question

Amongst $NO_3^ -$ , $AsO_3^{2 - }$ , $CO_3^{2 - }$ , $ClO_3^ -$ , $SO_3^{2 - }$ and $BO_3^{3 - }$ the non-planar species are:
$A.$ $CO_3^{2 - }$ , $SO_3^{2 - }$ and $BO_3^{3 - }$
$B.$ $AsO_3^{2 - }$ , $ClO_3^ -$ and $SO_3^{2 - }$
$C.$ $NO_3^ -$ , $CO_3^{2 - }$ and $BO_3^{3 - }$
$D.$ $SO_3^{2 - }$ , $NO_3^ -$ and $BO_3^{3 - }$

Answer 1

The molecule is planar and non-planar depending upon the shape of a molecule if in a molecule the atom arranges itself around the central molecules so they exist on a single two-dimensional plane molecule is planar. The molecules exist in a three dimensional form like tetrahedrons, octahedrons or bipyramids then the molecules are non planar.

Complete step by step answer:
The shape of a molecule can be predicted by VSEPR theory by determining their hybridization. Hybridization is a process of intermixing of two or more atomic orbitals from the same atom to form an entirely new orbital different from its component and hence being called hybrid orbital.
In the given question we have to first predict their hybridization and then by using their hybridization we also determine their shape
Table: the table summarizes the hybridization of species, their shape , bond pair , lone pair and planar and non planar:

Name of the species	Number of bond pair	Number of lone pair	Hybridization	Geometry	Planar or Non-planar
$NO_3^ -$	3	0	$s{p^2}$	Trigonal planar	Planar
$AsO_3^{2 - }$	3	1	$s{p^3}$	Pyramidal	Non-planar
$CO_3^{2 - }$	3	0	$s{p^2}$	Trigonal planar	Planar
$ClO_3^ -$	3	1	$s{p^3}$	Pyramidal	Non-planar
$SO_3^{2 - }$	3	1	$s{p^3}$	Pyramidal	Non-planar
$BO_3^{3 - }$	3	0	$s{p^2}$	Trigonal planar	Planar

Thus only three species are non-planar namely, $AsO_3^{2 - }$, $ClO_3^ -$ and $SO_3^{2 - }$ . So the correct option is $B$ .

Note:
Valence Shell Electron Pair Repulsion Theory $\left( {VSEPR} \right)$ .This is a very useful theory to predict the geometry or shape of a number of polyatomic molecules or ions on a non-transition element. This theory says that shapes of a species depend on the number of and nature of electron pairs surrounding the central atom of a species.Table summarizes the relationship between the number of electron pairs that is bond pair and lone pair and the shape or geometry.

Total number of electron pairs	Shape
2	Linear
3	Trigonal planar
4	Tetrahedral
5	Trigonal bipyramidal
6	Octahedral
7	Pentagonal bipyramidal