What is the equation for calculating specific rotation?

The equation for calculating specific rotation is given by [α] = α / (c l), where [α] represents the specific rotation, α is the observed rotation in degrees, c is the concentration of the solution (in grams per milliliter), and l is the path length of the sample cell in decimeters. This formula allows chemists to assess the optical activity of chiral substances and is particularly important in determining the purity and concentration of solutions containing optically active compounds.

In this context, specific rotation is a standardized way to compare the optical activity of different substances or the same substance in different concentrations. By dividing the observed rotation (α) by the product of the concentration (c) and the path length (l), the specific rotation provides a way to understand the inherent optical activity of a chiral compound, independent of the concentration or the amount of substance present.