What is the pH of a solution made by mixing 100.00 mL of 0.20 M HCl with 50.00 mL of 0.10 M HCl? Assume that the volumes are additive.
A)0.15
B)0.52
C)0.78
D)1.70

Question

Quizplus · Accepted Answer

Step 1: Calculate the total amount of moles of HCl in the solution:

moles HCl = (100.00 mL)(0.20 M) + (50.00 mL)(0.10 M) = 20.00 + 5.00 = 25.00 mmol HCl

Step 2: Calculate the total volume of the solution:

total volume = 100.00 mL + 50.00 mL = 150.00 mL = 0.150 L

Step 3: Calculate the concentration of HCl in the solution:

[HCl] = moles HCl / total volume = 25.00 mmol / 0.150 L = 166.67 mM

Step 4: Calculate the pH of the solution:

pH = -log[H+] = -log(166.67 x 10^-3) = 0.78

Therefore, the pH of the solution is 0.78, which corresponds to choice C.

What Is the PH of a Solution Made by Mixing