A chemist mixes 100.0 mL of 0.250 M HBr(aq) with three successive 16.7 mL aliquots of…
CHEMISTRY · Multi-part · A Level · Chemistry · Acids and bases · Acids and bases
Problem
A chemist mixes 100.0 mL of 0.250 M HBr(aq) with three successive 16.7 mL aliquots of 0.300 M NaOH(aq). The reactants are strong electrolytes, temperatures remain at 25 °C, and volumes are additive.
After each aliquot is added and thoroughly mixed, the chemist measures the solution pH.
(a) For the initial mixture (before any NaOH is added), calculate the pH.
(b) After the FIRST 16.7 mL addition of NaOH, calculate the pH of the solution. Show all stoichiometric reasoning.
(c) After the SECOND 16.7 mL addition of NaOH, calculate the pH of the solution.
(d) After the THIRD 16.7 mL addition of NaOH, calculate the pH of the solution.
(e) Using your results, construct a table that lists cumulative volume of NaOH added versus pH. Describe how the limiting–excess relationship changes across the three additions and identify at which point (if any) the solution is neutral.