CHEMISTRY · Multi-part · A Level · Chemistry · Acids and bases · Acids and bases
Problem
The bicarbonate ion, HCO3−, plays a critical role in maintaining human blood pH within a narrow range.
Answer the following questions about the chemical behavior of HCO3− in aqueous solution.
(a) Write a balanced chemical equation (including physical states) for the reaction that occurs when HCO3− behaves as a Brønsted–Lowry acid in the presence of aqueous hydroxide ion.
(b) Write a balanced chemical equation (including physical states) for the reaction that occurs when HCO3− behaves as a Brønsted–Lowry base in the presence of hydronium ion.
(c) For each equation written in parts (a) and (b), clearly identify the conjugate acid–base pair that is produced.
(d) Using the reactions you wrote, explain qualitatively how the presence of significant concentrations of HCO3− enables blood to resist large pH changes when small amounts of strong acid or strong base enter the bloodstream.