How many milliliters of glacial acetic acid (17.3 M) would you need to titrate an aqueous solution of 100 grams sodium acetate (MW = 82.0 g mol-1) to get a final pH of 5.00 and a final volume of 1.00 liter? The pK’ for acetic acid is 4.76. Show your work.
Use the Henderson-Hasselbalch equation.
pH = pKa + log(B/A)
5.00 = 4.76 + log(100.82)/x
Solve for x = mols acetic acid needed.
Then calculate mL of the 17.3 M acetic acid needed to produce that many mols for 1 L.
Note:I'm a little confused by the problem. I suppose one could ADD 17.3M acetic acid in a titration mode until the pH was 5.00 but I'm having a hard time understanding how we can think acetate + acetic acid ==> acetic acid. I think this is a decidedly different problem than adding acid to acetate to form acetic acid; i.e.,
Ac^- + H^+ ==> HAc.