Practice Identifying meso Compounds

A meso compound has multiple stereocenters but is optically inactive because it contains an internal plane of symmetry. The stereocenters within the molecule cancel each other out.

Look for an internal mirror plane that divides the molecule into two halves that are mirror images of each other. If one half has R configuration, the corresponding center on the other half must be S.

A meso compound is achiral despite having stereocenters. The internal symmetry makes the molecule superimposable on its mirror image, so it does not rotate plane-polarized light.

Yes, but only if the two stereocenters have opposite configurations (one R, one S) and the molecule has an internal plane of symmetry. If both are R or both are S, the molecule is chiral.