Calculating pH and pOH of Strong Acids and Bases
Name: ________________________________ Date: ______________ Block: ______________
1.
Calculate pH and pOH for the following monoprotic strong acids
a) 0.006 mol/L HI
(aq)
b) 0.02 mol/L HNO3
(aq)
2. To clean a clogged drain, 26 g of sodium hydroxide is added to water to make 150 mL of solution. What
are the pH and pOH values for this solution? [fist solve for the concentration of NaOH using C = n/V (L) ]
3.
Food scienctsists and dieticians measure the pH of foods when they devise recipes. Various measurements
related to their acidity are made and recored below. Complete the table below.
Food
[H+] mol/L
[OH-] mol/L
pH
pOH
Oranges
5.5 x 10-3
Asparagus
Olives
Blackberries
5.6
2.0 x 10-11
10.6
b) Based on pH only and assuming that sour taste is directly proportional to pH, which food listed above would
taste most sour?
Warner – SCH 4U
Calculating pH and pOH of Strong Acids and Bases
4. What mass of potassium hydroxide (KOH) is contained in 500 mL of solution that has a pH of 11.5?
Remember mass is calculated by n x MM.
5. Calculate the pH of a 0.032 mol/L Ba(OH)2 (aq) solution.
6. A solution is made by dissolving 0.8 g of Ca(OH)2 in water to makde 100 mL of a final solution. Calculate the
pH of the solution.
ANSWERS :
1. pH
a) 2.2
b) 1.6
pOH
11.8
12.4
2. 14.64
-0.64
4. 0.09 g
5. pH = 12.81
6. pH = 13.33
Warner – SCH 4U
2.
oranges
asparagus
olives
blackberry
[H+]
5.5 x 10-3 M
3.0 x 10-9 M
5.0 x 10-4 M
4.0 x 10-4 M
[OH-]
1.8 x 10-12 M
2.51 x 10-6 M
2.0 x 10-11 M
2.5 x 10-11 M
pH
2.26
8.4
3.3
3.4
pOH
11.74
5.6
10.7
10.6