how many moles of H⁺ would be left in the beaker after the reaction goes to completion?

Question

Consider the reaction of 75.0 mL of 0.350 M C₅H₅N (Kb = 1.7 x 10⁻⁹) with 100.0 mL of 0.405 M HCl. After 0.0263 moles of C₅H₅N and 0.0405 moles of H⁺ have reacted, how many moles of H⁺ would be left in the beaker after the reaction goes to completion?

Answer 1

C₅H₅N(aq) + HCl(aq) ==> C₅H₅NH⁺(aq) + Cl^-(aq) ... balanced equation for the acid-base reaction

Since the acid and the base react in a 1:1 mol ratio, we have....

0.0405 moles - 0.0263 moles = 0.0142 moles HCl left

Since HCl is a strong acid, it ionizes completely producing 0.0142 moles H⁺