After treating the water you need to decrease the pH back to 6.5. The water is held in a 200,000 gallon "pond".
a. You have a 3 M HCl solution. How many mLs of this solution are required to change the pH from 9.5 to 6.5?
b. Another option for lowering the pH is to add citric acid (C6H8O7). Citric acid has a pKa = 3.1. How many grams of citric acid do you need to add to a 200,000 gallon pond to lower the pH from 9.5 to 6.5?