![]() a substance which tends to combine with a proton. a substance which tends to dissociate to yield a proton, and a base is proton acceptor, i.e. The reactions which occur during many nonaqueous titrations can be explained by means of the concepts of the Brønsted-Lowry theory.Īccording to this theory an acid is a proton donor, i.e. Substances which are either too weakly basic or too weakly acidic to give sharp endpoints in aqueous solution can often be titrated in nonaqueous solvents. The effect of this is that the inflection in the titration curves for very weak acids and very weak bases is small, because they approach the pH limits in water of 14 or 0 respectively, thus making endpoint detection relatively more difficult.Ī general rule is that bases with p K a 7 cannot be determined accurately in aqueous solution. H 2O + B ⇌ OH - + BH + Competes with ROH + B ⇌ RO - + BH + H 2O + H + ⇌ H 3O + Competes with RNH 2 + H + ⇌ RNH 3 + The theory is that water behaves as both a weak acid and a weak base thus, in an aqueous environment, it can compete effectively with very weak acids and bases with regard to proton donation and acceptance, as shown below: 3 Titration of halogen acid salts of bases.
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