On the state of oxalic acid dissolved in water

Abstract

An apparatus for the determination of solubilities is described. The solubility of oxalic acid in water from 0"--80" has been measured. The form of the temperature-solubility curve shows that oxalic acid 2 aq. at the melting point is partially dissociated into anhydrous oxalic acid and water.From the solubilities at lower temperatures the heat of solution is calculated, correcting for the electrolytic dissociation. The value is in good accord with that which was found experimentally.It is concluded that in a solution of oxalic acid in water at temperatures below 70" practically all the molecules present are bound to (at least) two molecules of water, but that at higher temperatures an increasing dissociation into anhydrous acid and water takes place v .The solubility of oxalic acid in water at different temperatures has been measured by several investigators 1 ) 2 ) 3). Their results even at lower temperatures, are not so well in accord as might be expected.See table I.