Chromic Acid

Analysis method editing

Determination of chromic acid content in air: the sample was collected by filter, dissolved in sulfuric acid, and then determined by colorimetry after adding diphenylcarbazide (NIOSH method).

Determination of chromic acid content in water: the sample is extracted and determined by atomic absorption spectrometry or colorimetry.

Waste disposal method: the concentrated chromic acid waste liquid is converted into trivalent chromium after chemical reduction, and the pH value of the solution is adjusted to form precipitate, and the precipitate is landfilled as chemical waste. 

Usage editing

Chromic acid is the most common cleaning fluid used in the laboratory. It has both acidity and oxidizability. It can remove the dirt and insoluble substances from the inner and outer walls of experimental instruments. Usually, the washing solution is obtained by adding potassium dichromate into concentrated sulfuric acid, but hexavalent chromium is harmful to the environment, and sometimes the instrument is damaged in strong acidic environment, so the application of chromic acid lotion has been reduced.

Chromic acid can be used as oxidant. Many organic compounds can be oxidized by chromic acid, and many oxidants based on hexavalent chromium have been developed. Jones reagent: an aqueous solution of chromic acid, sulfuric acid, and acetone that oxidizes primary and secondary alcohols to corresponding carboxylic acids and ketones without affecting the unsaturated bonds. Pyridinium chloride chromate: prepared by chromium trioxide and pyridine hydrochloride, it can oxidize primary alcohol to aldehyde. Collins reagent: the adduct of chromium trioxide and pyridine.

Chromic acid can also be used for chromium plating, high purity metal chromium, pigment, mordant, medicine and coal contact, and in the production of some glazes and colored glasses.

Post time: Oct-24-2020