Nitric acid (HNO) greatly enhance the rate of reaction. Although chromium (Cr), iron (Fe), and aluminium (Al) readily dissolve in dilute nitric acid, the concentrated acid forms a metal-oxide layer that protects the bulk of the metal from further oxidation. The formation of this protective layer is called passivation. Typical passivation concentrations range from 20% to 50% by volume (see ASTM A967-05). Metals that are passivated by concentrated nitric acid are iron, cobalt, chromium, nickel, and aluminium. Being a powerful oxidizing acid, nitric acid reacts violently with many organic materials and the reactions may be explosive. The hydroxyl group will typically strip
Brønsted–Lowry acid–base theory to become its conjugate base, A. The base, B, can accept a proton to become its conjugate acid, HB. Most acid-base reactions are fast so that the components of the reaction are usually in dynamic equilibrium with each other. Consider the following acid–base reaction: Acetic acid, CHCOOH, is an acid because it donates a proton to water (HO) and becomes its conjugate base, the acetate ion (CHCOO). HO is a base because it accepts a proton from CHCOOH and becomes its conjugate acid, the hydronium ion, (HO). The reverse of an acid-base reaction is also an acid-base reaction, between the