1. Using the symbol H
2
M to represent maleic acid, what is the pH and M 2 concentration of a solution containing 0.100 M H
2
(a) pH = 1.46 and [M
(b) pH = 1.46 and [M
2] = 3.51 x 10
2-
M? For maleic acid pK
] = 4.68 x 10
-2 molar
-7 molar
1
(c) pH = 3.89 and [M 2]= 1.29 x 10 -4 molar
= 1.91 and pK
2
= 6.33.
2. The amino acid glycine (H
2
NCH
COOH group, and one for the -NH
3
2
COOH) has two equilibrium constants, one for the -
group. pK a
for -COOH = 2.350 and pK a
for -NH
3
=
9.778. At pH 6.06, which compounds or ions predominate in solution?
(a) A mixture of H
3
(b) A mixture of H
3
NCH
2
COOH and H
3
NCH
2
COO -
NCH
2
COO and H
2
NCH
2
COO 2-
(c) H
3
NCH
2
COO only
3. A 0.200 M solution of HCl is added to a solution containing 0.150 moles of sodium phosphate (Na
3
PO
4
). The resulting solution is then diluted to exactly 1.00 L, at which time the pH was found to be pH 8.00. What is the concentration of H
2
PO
4
- in the solution? For phosphoric acid, K a1
= 7.11 x 10 -3 , K a2
= 6.32 x 10 -8
(a) 0.0205 molar
(b) 0.150 molar
, and K a3
= 7.1 X 1013
(c) 0.0750 molar
.
4. Sulfurous acid (H
2
SO
[SO
3
2]?
3
) has pK a1
= 1.91 and pK a2
= 7.18. At what pH does [HSO
3
] =
(a) 1.91
(b) 4.54
(c) 7.18
5. Find the fraction of association of a 0.100 molar solution of hydrazoic acid. K a hydrazoic acid = 2.20 x 10 -5 . i.e. 
0
.
for
(a) 98.6%
(b) 1.45%
(c) 0.40%
6. Which of the following statements is true regarding the isoionic point and the isoelectric point?
(a) The isoionic point and the isoelectric point are the same thing.
(b) At the isoelectric point only the ions H
2
A + , A , H + , and OH are present and the concentrations of H
2
A + and A- are not equal to each other.
(c) At the isoelectric point, the average charge of the polyprotic acid is 0, and the concentration of H
2
A + is equal to the concentration of A .

7. How many grams of NaH
2
PO
4
would be added to 5.60 grams of Na
500.0 mL of a buffer at pH = 7.3? For H
3
PO
4
pK a1
= 2.148, pK
3
PO
4
to produce a2
= 7.199, and pK a3
=
12.15. (use Henderson-Hasselbach equation, HHE, note: both salts are in the same space so the mole ratio equals molar ratio. In applying HHE at buffer regions concentrations of conjugate pairs are concentrations of conjugate ions)
(a) 7.36 g NaH
2
PO
4
(b) 1.63 g NaH
2
(c) 5.73 g NaH
2
PO
4
PO
4
.
.
.
8. How many mL of 12.0 M HCl would be added to 500.0 mL of 0.100 M Na
2
SO
3
to produce a buffer with a pH of 7.50? Assume no volume change. For H
10 -2 and K a2
= 6.6 x 10 -8
2
SO
3
K a1
= 1.23 x
. (First figure out which pKa to deal with and think about the changes in the moles of the two buffering species as HCl is added).
(a) 1.36 mL HCl
(b) 2.81 mL HCl
(c) 4.17 mL HCl
9. What is the pH of a 0.100 M solution of potassium hydrogen phthalate, KHC
8
H
4
O
2
? For phthalic acid, pK a1
= 2.950 and pK a2
= 5.408.
(a) 1.98
(b) 3.20
(c) 4.18
10. Given a 0.100 M solution of the hypothetical diprotic acid H
2
M, calculate the fraction of species in the form H
2
M (α
H2M
). For H
2
M, K a1
(a) 3.12%
(b) 96.88%
= 1.0 x 10 -4 and K a2
= 1.0 x 10 -7 .
(c) 0.00%
11. How many mL of 12.0 M HCl should be added to 500 mL of 0.100 M Na
2
8.13 x 10 -13 change.
and K b1
=1.5 x 10 -7
SO
3
(K b2
=
) to produce a buffer at pH of 7.00? Assume no volume
(a) 2.51 mL
(b) 3.39 X 10 -5
(c) 8.11 mL
mL
12. Given the hypothetical acid H
4
A 2+
(a) H
4
A 2+
, what species determines the isoionic pH?
(b) A 2-
(c) H
2
A

13. Given the hypothetical acid H
4
A 2+ (pK a1
= 1.4, pK a2
= 3.44, pK
8.45), what is the principle species in solution at pH = 9.00?
(a) H
(b) A
(c) H
3
2-
2
A +
A a3
= 6.01, and pK a4
=
14. Given the hypothetical acid H
4 the isoelectric pH?
A 2+ , the concentration of which species are equal at
(a) [H
4
A 2+
(b) [H
3
A +
(c) [H
2
] = [H
] = [HA
A] = [HA -
3
-
]
A
]
+ ]
15. Calculate the pH for 0.200 M KHA (K a1
= 1.00 x 10 -5 and K a2
= 1.00 x 10 -9 .
(a) 2.849
(b) 11.151
(c) 7.000