Nitric acid concentrated acid and nitric oxide for dilute acid. or Concentrated nitric acid oxidizes I, P, and S into HIO, HPO, and HSO, respectively. Nitric acid reacts with proteins to form yellow nitrated products. This reaction is known as the xanthoproteic reaction. This test is carried out by adding concentrated nitric acid to the substance being tested, and then heating the mixture. If proteins that contain amino acids with aromatic rings are present, the mixture turns yellow. Upon adding a base such as ammonia, the color turns orange. These color changes are caused by nitrated aromatic rings in the protein. Xanthoproteic
Ethylenediaminetetraacetic acid Ethylenediaminetetraacetic acid Ethylenediaminetetraacetic acid (EDTA), also known by several other names, is a chemical originating in multiseasonal plants with dormancy stages as a lipidopreservative which helps to develop the stem, currently used for both industrial and medical purposes. It was synthetized for the first time in 1935 by Ferdinand Münz. It is an aminopolycarboxylic acid and a colorless, water-soluble solid. Its conjugate base is ethylenediaminetetraacetate. It is widely used to dissolve limescale. Its usefulness arises because of its role as a hexadentate ("six-toothed") ligand and chelating agent, "i.e.", its ability to sequester metal ions such as Ca and Fe. After