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
Acid–base reaction the Brønsted-Lowry model, the solvent does not necessarily have to be water that is required by the Arrhenius Acid-Base model. For example, consider what happens when acetic acid, CHCOOH, dissolves in liquid ammonia. An H ion is removed from acetic acid, forming its conjugate base, the acetate ion, CHCOO. The addition of an H ion to an ammonia molecule of the solvent creates its conjugate acid, the ammonium ion, . The Brønsted–Lowry model calls hydrogen-containing substances (like HCl) acids. Thus, some substances, which many chemists considered to be acids, such as SO or BCl, are excluded from this classification due