Acids and bases

A wastewater is simulated as a solution containing \(10^{-2.7} \mathrm{M}  \mathrm{NaHCO}_{3}\) and \(10^{-3} \mathrm{M} \mathrm{NH}_{4} \mathrm{Cl}\)

a. List the dissolved species that you expect to be present in solution.

b. Prepare a log \(C-p H\) diagram for the system, and calculate the \(\mathrm{pH}\) of the solution.

c. In order to remove nitrogen by volatilizing \(\mathrm{NH}_{3}\) gas, \(148 \mathrm{mg} / \mathrm{L}\) Ca(OH) \(_{2}\) (lime) will be added to raise the \(\mathrm{pH}\) and convert \(\mathrm{NH}_{4}^{+}\) to the \(\mathrm{NH}_{3}(a q)\) form. Calculate the \(\mathrm{pH}\) after lime addition. (Assume that no \(\mathrm{CaCO}_{3}\) precipitation or ammonia loss takes place during lime addition.)

\(d\). If \(\mathrm{CaCO}_{3}\) precipitation did occur during lime addition, would it raise, lower, or not change the \(\mathrm{pH}\) of the solution? (Hint: Consider what species are removed from solution by this reaction, and what the response would be of the species that remain.)

e. Would removal of \(\mathrm{NH}_{3}(a q)\) by volatilization raise, lower, or not change the \(\mathrm{pH}\) of the solution? Explain your reasoning briefly.