Asked by Tim
I understand part (I) but We have only briefly gone over the HH equation in class and I understand how to use it to get the pH but I really don't understand how to use it in part (II), assuming I should be using it in this question?
(I)Calculate the pH of an acetate buffer containing 27.5 mM acetic acid (pKa is 4.74) and 50 mM
sodium acetate.
(II) When a 100 mM aq solution of sodium acetate was prepared in the lab it had a
pH of 8.9. Calculate the amount of acetic acid (in g) to be added to 0.5 L of this sodium acetate
solution in order to bring its pH to the target value of 5.00.
(I)Calculate the pH of an acetate buffer containing 27.5 mM acetic acid (pKa is 4.74) and 50 mM
sodium acetate.
(II) When a 100 mM aq solution of sodium acetate was prepared in the lab it had a
pH of 8.9. Calculate the amount of acetic acid (in g) to be added to 0.5 L of this sodium acetate
solution in order to bring its pH to the target value of 5.00.
Answers
Answered by
DrBob222
For part II, plug into the HH equation.
5.00 = 4.74 + log (base)/(acid)
5.00 = 4.74 + log (100*0.5)/(x)
Solve for x = mmols acetic acid and convert that to grams acetic acid.
5.00 = 4.74 + log (base)/(acid)
5.00 = 4.74 + log (100*0.5)/(x)
Solve for x = mmols acetic acid and convert that to grams acetic acid.