Investigating pH in Acid-Base Solutions

1. 10 mL of M HCl solution is mixed with 150 mL of water to make a new HCl solution. What is the pH of the resultant solution? Justify your answer.

2. Let’s prepare an H2SO4 solution by dissolving 4.9 grams of H2SO4 in 100 mL of water.
a. How many H2SO4 molecules are in this solution?
b. What is the molarity of the solution?
c. What is the pH of the solution?
d. What is the pH of the solution if 3.0 grams of NaOH are added to the solution?
Note: Sulfuric acid (H2SO4) is a diprotic acid. The dissociation constant of the first proton (H+) is significantly larger than the second H+ dissociation. So, the pH of such a solution is mainly contributed by the first proton dissociation, while the second proton dissociation will provide some modification to its pH value. If you haven’t learned polyprotic acids yet, consider one H+ dissociation is enough to be awarded full credit.