The disulphuric acid solvent system. Part II. Cryoscopic and conductimetric measurements on some organic and inorganic bases

Abstract

Cryoscopic and conductimetric measurements on a number of weak organic bases have shown that they are more extensively ionized in disulphuric acid than in sulphuric acid or fluorosulphuric acid. It is concluded that disulphuric acid is a more acidic medium than either of these other solvents. It is shown how the cryoscopic data for any solute may be interpreted to give a value for ν, the total number of moles of all species except sulphuric acid, formed in solution by one mole of a solute, and also a value for the number of moles of sulphuric acid. The conductimetric data may be interpreted to give the number of moles of HS₃O₁₀^– and H₂SO₄ formed by each mole of solute. The results of the conductimetric and cryoscopic measurements show that HClO₄ behaves as a very weak base and that KCl and KF give quantitative formation of HSO₃Cl and HSO₃F respectively, both of which behave as nonelectrolytes. KlO₃ forms lO₂SO₄H and KH₂PO₄ gives the P(OH)₄⁺ ion. Nitric acid gives the nitronium ion, and triphenylmethanol the triphenylcarbonium ion. A number of carboxylic acids, are shown to be dehydrated to the corresponding acyl ion, e.g., CH₃CO₂H→CH₃CO⁺.