Geometrical isomerism is a type of stereoisomerism. Stereoisomers are molecules that have the same molecular formula and the same connectivity of atoms, but differ in the arrangement of their atoms in space. Geometrical isomers are a type of stereoisomers that differ in the spatial arrangement of substituents around a double bond or a cyclic structure.

Explanation:

Geometrical isomerism arises due to the restricted rotation around a double bond or a cyclic structure. In such cases, the substituents present on either side of the double bond or in the ring structure cannot rotate freely around the bond or the ring due to steric hindrance. This results in two different spatial arrangements of the substituents around the bond or the ring.

In the case of a double bond, there are two possible geometrical isomers - cis and trans. In the cis isomer, the two identical substituents are present on the same side of the double bond, while in the trans isomer, the two identical substituents are present on the opposite sides of the double bond. In the case of a cyclic structure, there are two possible geometrical isomers - cis and trans, which differ in the spatial arrangement of the substituents on the ring.

Geometrical isomers have different physical and chemical properties, such as melting point, boiling point, solubility, reactivity, and biological activity. For example, the cis isomer of 1,2-dichloroethene has a higher boiling point and is more polar than the trans isomer due to the dipole-dipole interactions between the two chlorine atoms.

In conclusion, geometrical isomerism is a type of stereoisomerism that arises due to the restricted rotation around a double bond or a cyclic structure. Geometrical isomers have different spatial arrangements of substituents around the bond or the ring, resulting in different physical and chemical properties.

Since geometrical isomerism arrises due to the change in geometry of cis-trans isomer which falls in steriomers which means same molecular formula and structural formula but different 3-dimensional arrangement