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,
Thiosulfurous acid They are immiscible in water, but dissolve in benzene or carbon tetrachloride. These species are less rigid than the thiosulfite esters. Thiosulfurous acid Thiosulfurous acid (HS−S(=O)−OH) is a low oxidation state (+1) sulfur acid. It is the equivalent acid for disulfur monoxide. Thiosulfurous acid is formed by reacting hydrogen sulfide and sulfur dioxide at room temperature. The thiosulfurous acid molecule is unstable when condensed, reacting with itself. It decomposes to polysulfane oxide or polythionic acids in water which is termed Wakenroder's liquid. Other possible isomers are dihydroxydisulfane or hypodithionous acid HOSSOH, a linear chain, and thiothionyl hydroxide (S=S(OH)) a tautomer