Question

What is Inversion?

Answer 1

Hint: The property of an organic compound that rotates plane polarised light (produced by passing ordinary light through a Nicol prism) when it is passed through their solutions is known as optical activity, and the compounds are known as optically active compounds.

Complete answer:
Inversion is a chemical reaction that changes the direction of optical rotation of a substance from dextrorotatory (d) to levorotatory (l) or vice versa. Inversion of the spatial re-arrangement of atoms or groups of atoms in a dissymmetric molecule produces a molecular structure form that is a mirror image of the original molecule in chemistry.
The Latin word dexter is the source of the prefix dextro. It means "to the right" or "on the right side." The Latin word laevo is the source of the prefix levo. It means "to the left" or "on the left side." The molecule is dextrorotatory if the plane of polarised light is rotated clockwise as it approaches the observer (to the right if you're driving a car) (d). The molecule is levorotatory if the plane of polarised light is rotated counterclockwise (to the left) (l). For instance, glucose comes in two forms: D-glucose and L-glucose. The letters D and L do not refer to the polarised light's rotational direction. They refer to the Fischer projections instead.
When a substance's solution is placed in the path of plane-polarized light, its optical activity is a measure of the substance's ability to rotate the polarisation plane.

Note:
Walden Inversion is the phenomenon of configuration inversion during a chemical reaction. Optical inversion is the common name for Walden inversion. The inversion of the configuration may or may not result in a shift in rotational direction. In a chemical reaction, Walden's inversion is the reversal of a chiral centre in a molecule. The Walden inversion changes the structure of the molecule from one enantiomeric form to the other because the molecule can form two enantiomers around the chiral centre.