The concentration of nitrate ion can be determined by a multistep process. A sample of water of volume 25.00 mL from a rural well contaminated with NO₃^–(aq) was made basic and treated with an excess of zinc metal, which reduces the nitrate ion to ammonia. The evolved ammonia gas was passed into 50.00 mL of 2.50 * 10^–3 m HCl(aq). The unreacted HCl(aq) was titrated to the stoichiometric point with 28.22 mL of 1.50 * 10^–3 m NaOH(aq).

(a) Write balanced chemical equations for the three reactions.

(b) What is the molar concentration of nitrate ion in the well water?