Note 59 — Chapter XX · SULPHUR, SELENIUM, AND TELLURIUM

For example, the action of hot sulphuric acid on nitrogenous compounds, as applied in Kjeldahl's method for the estimation of nitrogen (Volume I. p. 249). It is obvious that when sulphuric acid acts as an oxidising agent it forms sulphurous anhydride.

The action of sulphuric acid on the alcohols is exactly similar to its action on alkalis, because the alcohols, like alkalis, react on acids; a molecule of alcohol with a molecule of sulphuric acid separates water and forms an acid ethereal salt—that is there is produced an ethereal compound corresponding with acid salts. Thus, for example, the action of sulphuric acid, H₂SO₄, on ordinary alcohol, C₂H₅OH, gives water and sulphovinic acid, C₂H₅HSO₄—that is, sulphuric acid in which one atom of hydrogen is replaced by the radicle C₂H₅ of ethyl alcohol, SO₂(OH)(OC₂H₅), or, what is the same thing, the hydrogen in alcohol is replaced by the radicle (sulphoxyl) of sulphuric acid, C₂H₅O.SO₂(OH).