a 3. For each of the solutions below, determine the pH at equilibrium if 0.15 mmol/L of HCl is added. a. (10 pts) Pure water b. (35 pts) A buffered water to which a combination of H2CO3 and NaCO, has been added, which has a total carbonate concentration (Ct) of 100 mmol/L and a pH of 7. Assume [CO;2-) is negligible at all times, no exchange of carbonate/CO2 with the atmosphere occurs (Ct is constant), and the following reactions are relevant: H2CO3 + HCO3+ +H PKA = 6.3 Water dissociation pKw - 14 Hint: first determine the concentration of Nat initially present at pH 7 W before HCl is added. Also, Ct = [H,CO:]+[HCO,11