Phosphorous acid

Phosphorous acid is a chemical compound. It is an acid. Its chemical formula is H3PO3. It contains hydrogen and phosphite ions.

Properties
It is a white solid. It absorbs water. It is a strong reducing agent. It can be deprotonated twice. When it is heated, it turns into phosphoric acid and phosphine. It is toxic. Salts of phosphorous acid is called phosphites. It reacts with mercury(II) chloride to make mercury(I) chloride. If it still is kept, it reacts with mercury(I) chloride to make mercury.

Preparation
It is made by reacting phosphorus(III) oxide with water. It is also prepared by reaction of phosphorus trichloride with water, which produces hydrochloric acid too. 

Uses
It is used as a reducing agent. It is also used to kill certain bacteria that grow on plants.

Related pages
Hypophosphorous acid
Phosphorus

Category:Phosphorus compounds