9-15. RELATIONSHIP BETWEEN pH AND pOH
+
-
Kw = [H ] [OH ] = 1.0 X 10-14
pKw = pH + pOH
14 = pH + pOH
a. Example 1. What is the pOH of a H2SO4 solution that has a pH of 4.3?
Solution. Select the expression that allows you to solve for the unknown
quantity.
14 = pH + pOH
Substitute the given information, and solve for the unknown quantity.
14 = 4.3 + pOH
pOH = 14 - 4.3
pOH = 9.7
b. Example 2. What is the pH of a 0.010 mol/L NaOH solution?
Solution. In solving this problem, it is necessary to first determine the pOH of
the solution before solving for the pH.
1
pOH = log ------= 2.00
0.010
Now, utilize the expression that relates pH to pOH by substituting the given
information and solving for the unknown quantity.
14 = pH + pOH
14 = pH + 2.00
pH = 14 - 2.00
pH = 12.00
MD0837
9-12
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