A chemist mixes of hydrochloric acid with of sodium hydroxide at
CHEMISTRY · Multi-part · A Level · Chemistry · Acids and bases · Acids and bases
Problem
A chemist mixes 25.0mL of 0.100M hydrochloric acid with 15.0mL of 0.150M sodium hydroxide at 25∘C. Both substances completely dissociate in water, and the final volume is the simple sum of the two solutions.
(a) Calculate the initial moles of hydronium ions and hydroxide ions present before mixing.
(b) Determine which ion is in excess after the reaction between the strong acid and strong base goes to completion, and compute the moles of that excess ion.
(c) Find the molar concentration of the excess ion in the final mixture.
(d) Calculate the pH of the final solution, reporting the value to the appropriate number of significant figures. Clearly explain each step of your reasoning.