Hypophosphorous acid can also be made by passing sodium hypophosphite through a cation exchange column, where sodium is exchanged for hydrogen. This process requires a very large cation exchange column, and also generates an aqueous waste stream that contains phosphorus, which is difficult to dispose of.
Sodium hypophosphite monohydrate is used for electroless nickel plating agent and water treatment agent. It is also used in petroleum fields. Further, it is used as a food additive. In addition, it reduces nickel ions in solution to metallic nickel on metal substrates as well as on plastic substrates.
Hypophosphoric acid can be prepared by the reaction of red phosphorus with sodium chlorite at room temperature. A mixture of hypophosphoric acid, phosphorous acid (H3PO3) and phosphoric acid (H3PO4) is produced when white phosphorus oxidises in air when partially immersed in water.
