Question

Carbon dioxide ( $C{O_2}$ ) is isostructural to which of the following compounds:
A. ${N_2}^ +$
B. $SnC{l_2}$
C. ${C_2}{H_2}$
D. $N{O_2}$

Answer 1

Hint : Isostructural indicates that two or more molecules will be having similar chemical structure. Two molecules are said to be isostructural, if they have the same structure and the same hybridisation , but it is not necessary that they should have the same chemical composition. For such questions we will draw the structures of every molecule and see which of the structures is the same to that of Carbon dioxide.

Complete step by step solution :
Firstly, as we know that $C{O_2}$ is a covalent molecule and at the centre a carbon atom is joined by two pairs of double bonds to the oxygen atom and is a linear molecule.
A. Now, In ${N_2}^ +$ the two nitrogen atoms are bonded by a triple bond with a positive charge on one Nitrogen atom and this is also a linear molecule. Hence, $C{O_2}$ is isostructural to ${N_2}^ +$ .
B. Now, In $SnC{l_2}$ the Sn atom is bonded by single bonds to two chlorine atoms but has a lone pair on the central atom and therefore, is a non-linear molecule. Hence, $C{O_2}$ is not isostructural to $SnC{l_2}$ .
C. Now, In ${C_2}{H_2}$ also known as ethylene molecule the two hydrogen atoms are bonded by a single bond with a triple bond between two C atoms and this is a linear molecule, and its hybridisation is same as that of $C{O_2}$ . Hence, $C{O_2}$ is isostructural to ${C_2}{H_2}$ .
D. Now, In $N{O_2}$ the nitrogen atoms are bonded by double bonds to two oxygen atoms but have a lone pair and are a non-linear molecule. Hence $C{O_2}$ is not isostructural to $N{O_2}$ .
So, the answer is ${N_2}^ +$ and ${C_2}{H_2}$ (Option A and C).

Note : A student can confuse in some cases where the chemical structure is same but still those are not isostructural; this might be the case because of the difference in the hybridisations of the two molecules.