What is the pH of a solution made by mixing 20.00 mL of 0.100 M HCl with 40.00 mL of 0.100 M KOH? Assume that the volumes of the solutions are additive.
A)0.48
B)1.48
C)12.52
D)13.52

Question

Quizplus · Accepted Answer

The reaction between HCl and KOH is a neutralization reaction, where HCl (a strong acid) reacts with KOH (a strong base) to form KCl (a salt) and H2O (water). The stoichiometry of the reaction is 1:1, meaning one mole of HCl reacts with one mole of KOH. In this case, 20.00 mL of 0.100 M HCl contains 0.002 moles of HCl, and 40.00 mL of 0.100 M KOH contains 0.004 moles of KOH. After the reaction, there will be an excess of 0.002 moles of KOH in a total volume of 60.00 mL (20.00 mL + 40.00 mL). The concentration of KOH is then 0.002 moles / 0.060 L = 0.0333 M. Since KOH is a strong base, its pOH is -log(0.0333) = 1.48. The pH can be found by subtracting the pOH from 14, which gives a pH of 14 - 1.48 = 12.52.

What Is the PH of a Solution Made by Mixing