磷酸

it is colorless crytal with relative density of 1.651,melting point of 73.6°C,boiling point of 200°C .it can be easily dissolved into water and mellow .it slowly oxidizes into orthophosphoric acid in the air and when heat up at 180°C it decomposes to orthophosphoric acid and phosphine .the phosprous acid is thbinary acid.its acidity is slightly stronger than the phosphoric acid .it also has strong reducibility .it can easily ruduct Ag+Ion to metal silver and sulfurie acid to sulphur dioxide .it has strong water absorbatility,deliquescence and corrosiveness.it can bu served as redusing agent,nylon brightening agent as well as phosphite raw material and pesticide intermediates.