Chromic Acid Flakes is also called Chromium Trioxide or Chromic Acid Anhydride. This is available in the form of small flakes of dark red or chocolate coloured appearance, which are easy to dissolve in water. It is hygroscopic in nature and forms a saturated of 62.6% CrO3 at 25 degrees Centigrade. Though it is an acid, dilute solutions of it exert a protective action on metal surfaces like mild steel, zinc, aluminum, copper, brass etc. at room temperature, by the formation of a thin passivating film.