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|Section2= |Section3= |Section7= |Section8= }} Hypophosphorous acid is a phosphorus oxoacid and a powerful reducing agent with molecular formula H3PO2. Inorganic chemists refer to the free acid by this name (also as "HPA"), or the acceptable name of phosphinic acid. It is a colorless low-melting compound, which is soluble in water, dioxane, and alcohols. The formula for hypophosphorous acid is generally written H3PO2, but a more descriptive presentation is HOP(O)H2 which highlights its monoprotic character. Salts derived from this acid are called phosphinates (hypophosphites). HOP(O)H2 exists in equilibrium with the minor tautomer HP(OH)2. Sometimes the minor tautomer is called hypophosphorous acid and the major tautomer is called phosphinic acid. ==Preparation and availability== The acid is prepared industrially via a two step process. Hypophosphite salts of the alkali and alkaline earth metals result from treatment of white phosphorus with hot aqueous solution of the appropriate hydroxide, e.g. Ca(OH)2. :P4 + 3OH− + 3H2O → 3H2PO2− + PH3 The free acid may be prepared by the action of a strong acid on these hypophosphite salts. :H2PO2− + H+ → H3PO2 Alternatively, H3PO2 arises by the oxidation of phosphine with iodine in water. :PH3 + 2I2 + 2H2O → H3PO2 + 4I− + 4H+ HPA is usually supplied as a 50% aqueous solution. 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「hypophosphorous acid」の詳細全文を読む スポンサード リンク
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