Question

Which of the above is a pair of geometrical isomers?

• A. I and II
• B. I and III
• C. II and IV
• D. III and IV

Answer 1

The correct option is C

II and IV

Explanation for the correct option:

(C) II and IV

Geometric isomers:

• “Geometric isomers are two or more coordination compounds which contain the same number and types of atoms, and bonds but which have different spatial arrangements of the atoms.”
• The bonding connection must be confirmed in order to identify geometric isomerism.
• Geometric isomers can be found in molecules with the same bonding connection.
• Thus, the pairs of geometric isomers are given below:

Explanation for the incorrect option:

(A) I and II

• The type of atom is not the same in these structures. Thus, these pairs are not geometrical isomers.
• Thus, these pairs are not geometrical isomers.

(B) I and III

• The type of atom is not the same in these structures.
• Thus, these pairs are not geometrical isomers.

(D) III and IV

• Geometrical isomers will have various spatial arrangements of substituents and the same bonding connectivity since they are also stereoisomers.
• In Molecules III and IV, the bonding connection is the same.
• $\mathrm{Cl}$ and $\mathrm{H}$ are connected to one carbon, while $\mathrm{Br}$ and ${\mathrm{CH}}_3$ are connected to the carbon next to it, but in different ways in both molecules.
• Thus, these pairs are not geometrical isomers.

Therefore, the correct option is (C) II and IV