Substitute the given information, and solve for the unknown quantity.
1.50 X 10-3 mol/L
pOH = 4.75 + log ------------------
2.00 X 10-4 mol/L
pOH = 4.75 + 0.8751
pOH = 5.63
Now that you have determined the pOH, using the appropriate expression,
determine the pH of the buffer.
14 = pH + pOH
pH = 14 - pOH
pH = 14 - 5.63
pH = 8.37
c. Example 3. What amount of salt/acid is required to prepare a 0.100 mol/L
acetate buffer at a pH of 5.50? The pKa of acetic acid is 4.76.
Solution. At times, the pK of the acid/base of a buffer and the total
concentration of the buffer is known, and the amount of salt and acid/base required to
prepare a buffer must be calculated.
After reading the problem carefully, select the expression that allows you to
solve for the unknown quantity.
pH = pKa + log ------