The hydrogen carbonate ion (HCO₃^-) can act both as an acid and as a base.
i. Write a chemical equation that shows HCO₃^- acting as an acid when it reacts with water.
Solution

ii. Write a chemical equation that shows HCO₃^-
– acting as a base when it reacts with water.
Solution.

Hypochlorous acid (HOCl) is a weak acid with an acidity constant, Ka, of 3.0 × 10–^-8 M at 25°C. Calculate the pH of a 0.50 M solution of hypochlorous acid at that temperature.
Solution

The hydrogen ion concentration of a solution is described by the term pH. The hydroxide ion (OH^-–) concentration is described in the same way by the term pOH.
A solution has a pOH of 3 at 25°C.
i. Calculate the hydroxide ion concentration of the solution, in mol/L
Solution.

ii. Calculate the hydrogen ion concentration of the solution, in mol/L–
Solution.