A student is tasked with determining the concentration of a hydrochloric acid…
CHEMISTRY · Multi-part · AP · Chemistry · Acids and Bases · Acids and Bases
Problem
A student is tasked with determining the concentration of a hydrochloric acid solution by titration with standardized sodium hydroxide.
A 25.00 mL aliquot of the unknown HCl is placed in an Erlenmeyer flask. The NaOH titrant has a concentration of 0.120 mol L⁻¹ and is delivered from a buret that can be read to the nearest 0.02 mL.
(1) Write the balanced molecular equation for the reaction that occurs during the titration.
(2) Calculate the exact volume of the NaOH titrant (in mL) required to reach the equivalence point if the concentration of the unknown HCl is 0.100 mol L⁻¹. Show all reasoning and include appropriate units.
(3) Suppose the student inadvertently overshoots the endpoint by 0.08 mL of NaOH. Calculate the resulting percentage error in the determined concentration of HCl, and explain whether the reported concentration would be too high or too low.