How are dihydroxy derivatives of benzene named, and what are their common names?

Dihydroxy derivatives of benzene are named by indicating the positions of the hydroxy (-OH) groups with numbers, starting from the lowest-numbered carbon. The IUPAC name uses the suffix “-diol” and the prefix “dihydroxybenzene.” Commonly, these compounds are known by their traditional names: ortho-dihydroxybenzene for 1,2-dihydroxybenzene, commonly called catechol; meta-dihydroxybenzene for 1,3-dihydroxybenzene, commonly called resorcinol; and para-dihydroxybenzene for 1,4-dihydroxybenzene, commonly called hydroquinone. These names reflect the relative positions of the hydroxy groups on the benzene ring.