text: PBr evolves corrosive HBr, which is toxic, and reacts violently with water and alcohols.
  :PBr + 3 HO → HPO + 3 HBr
  In reactions that produce phosphorous acid as a by-product, when working up by distillation be aware that this can decompose above about 160 °C to give phosphine which can cause explosions in contact with air.