What is the expected melting point of pure S,S-hydrobenzoin compared to pure R,R-hydrobenzoin?

The expected melting point of pure S,S-hydrobenzoin and pure R,R-hydrobenzoin is indeed the same, both around 148°C. This is because both compounds are enantiomers, meaning they have the same molecular formula and structural features, differing only in the orientation of their substituents in space. Enantiomers have identical physical properties such as melting points and boiling points when pure.

In practice, the melting point of a substance is a characteristic property that can be used to help identify it. Pure samples of enantiomers will exhibit sharp melting points, and since S,S-hydrobenzoin and R,R-hydrobenzoin are mirror images of each other, they will both exhibit the same melting behavior. Hence, when comparing the two, their melting points are expected to be the same.

Understanding this concept is essential in organic chemistry, as it illustrates the interplay between stereochemistry and physical properties. The scenario with enantiomers emphasizes that the molecular arrangement, while it alters interactions such as optical activity, does not inherently change shared physical characteristics in pure forms.