Nitric acid Nitric acid can oxidize non-active metals such as copper and silver. With these non-active or less electropositive metals the products depend on temperature and the acid concentration. For example, copper reacts with dilute nitric acid at ambient temperatures with a 3:8 stoichiometry: The nitric oxide produced may react with atmospheric oxygen to give nitrogen dioxide. With more concentrated nitric acid, nitrogen dioxide is produced directly in a reaction with 1:4 stoichiometry: Upon reaction with nitric acid, most metals give the corresponding nitrates. Some metalloids and metals give the oxides; for instance, Sn, As, Sb, and Ti are oxidized into SnO,
Phenylboronic acid with BBr, followed by hydrolysis form phenylboronic acid. Aryl halides or triflates can be coupled with diboronyl reagents using transition metal catalysts. Aromatic C-H functionalization can also be done using transition metal catalysts. The dehydration of boronic acids gives boroxines, the trimeric anhydrides of phenylboronic acid. The dehydration reaction is driven thermally, sometimes with a dehydration agent. Phenylboronic acid participates in numerous cross coupling reactions where is serves as a source of a phenyl group. One example is the Suzuki reaction where, in the presence of a Pd(0) catalyst and base, phenylboronic acid and vinyl halides are coupled to produce