Question

Challenges of international compensation

Answer 1

In case of racemic mixtures, which are 50-50% mixture of enantiomers, the net rotation is zero, because rotation of one enantiomer is always compensated by rotation of another enantiomer, thus, it is known as external compensation.
In case of meso compounds, which has two chiral centers, the configuration of the compound is either R,S or S,R. Looking into the optical activity, meso compounds(contain plane of symmetry) are optically inactive as rotation of one chiral center is compensated by rotation of second chiral center and since, the rotation occurs within the molecule, it is known as internal compensation