What are epimers? answer Diastereomers of an aldose sugar differing only in the configuration about the second carbon atom	Why cannot Grignard reagents be used with reactants or solvents that contain -OH, -COOH, -NH-, -NH2, or -SH groups? answer A Grignard reagent behaves as if it contained a carbanion and so is a strong base. If one of the groups above is present, the Grignard reagent will combine with H+ from it and become deactivated.
Why is the benzene ring more susceptible to substitution than to addition? answer The benzene ring is very stable due to the delocalization of pi electrons (resonance stabilization). An addition reaction on the ring would disrupt its aromatic structure; thus, this type of reaction is not very spontaneous. On the other hand, the pi electrons facilitate electrophilic substitutions.	On an NMR spectrum, a quartet is caused by how many nearby non-equivalent protons? answer 3