pH + pOH = pKw
pKa + pKb = pKw
Ka Kb = Kw
pH = pKa + log (cb/ca)
pH= pKa + log (nb/na)
pKw = 14.00



1.
Which of the following pairs has the stronger acid listed first?
A.
HBr, HI
B.
HClO2, HClO3
C.
H2SeO4, H2SeO3
D.
HNO2, HNO3
E.
HF, HCl


2.
Which of the following acids has the lowest pH?
A.
0.1 M HA, pKa = 4.55
B.
0.1 M HST, pKa = 11.89
C.
0.1 M HMO, pKa = 8.23
D.
0.1 M HBO, pKa = 2.43
E.
pure water


3.
What is the pH of a 0.0035 M KOH solution?
A.
2.46
B.
5.65
C.
8.35
D.
11.54
E.
12.83


4.
Which one of the following pairs is not a conjugate acid-base pair?
A.
H2O/OH-
B.
H2O2/HO2-
C.
OH-/O2-
D.
H2PO4-/HPO42-
E.
HCl/H+


5.
The acid dissociation constant Ka equals 1.26×10-2 for HSO4- and is 5.6×10-10 for NH4+. Which statement about the following equilibrium is correct?
HSO4-(aq)   +   NH3(aq)   ↔   SO42-(aq)   +   NH4+(aq)
A.
The reactants will be favored because ammonia is a stronger base than the sulfate anion.
B.
The products will be favored because the hydrogen sulfate ion is a stronger acid than the ammonium ion.
C.
Neither reactants or products will be favored because all of the species are weak acids or bases.
D.
The initial concentrations of the hydrogen sulfate ion and ammonia must be known before any prediction can be made.
E.
This reaction is impossible to predict, since the strong acid and the weak base appear on the same side of the equation.


6.
Farmers who raise cotton once used arsenic acid, H3AsO4, as a defoliant at harvest time. Arsenic acid is a polyprotic acid with Ka1 = 2.5×10-4, Ka2 = 5.6×10-8, and Ka3 = 3×10-13. What is the pH of a 0.500 M solution of arsenic acid?
A.
0.85
B.
1.95
C.
3.90
D.
4.51
E.
3.14


7.
What is the value of Kb for the cyanide anion, CN-? Ka(HCN) = 6×10-10
A.
5 × 10-3
B.
2 × 10-5
C.
4 × 10-5
D.
4 × 10-10
E.
4 × 10-24


8.
A solution is prepared by adding 0.10 mol of sodium sulfide, Na2S, to 1.00 L of water. Which statement about the solution is correct?
A.
The solution is basic.
B.
The solution is neutral.
C.
The solution is acidic.
D.
The concentration of sodium ions and sulfide ions will be identical.
E.
The concentration of sulfide ions will be greater than the concentration of sodium ions.


9.
Which one of the following substances will give an aqueous solution of pH < 7?
A.
KI
B.
NH4Br
C.
Na2CO3
D.
CH3COONa
E.
LiOH


10.
Which one of the following is a Lewis acid but not a Brønsted-Lowry acid?
A.
Fe3+
B.
H3O+
C.
HSO4-
D.
NH3
E.
H2O


11.
Which of the following aqueous mixtures would be a buffer system?
A.
HCl, NaCl
B.
HNO3, NaNO3
C.
H3PO4, H2PO4-
D.
H2SO4, CH3COOH
E.
NH3, NaOH


12.
Which of the following acids should be used to prepare a buffer with a pH of 4.5?
A.
HOC6H4OCOOH, Ka = 1.0 × 10-3
B.
C6H4(COOH)2, Ka = 2.9 × 10-4
C.
CH3COOH, Ka = 1.8 × 10-5
D.
C5H5O5COOH, Ka = 4.0 × 10-6
E.
HBrO, Ka = 2.3 × 10-9


13.
What is the pH of a buffer that consists of 0.45 M CH3COOH and 0.35 M CH3COONa? Ka(CH3COOH) = 1.8×10-5
A.
4.49
B.
4.64
C.
4.85
D.
5.00
E.
5.52


14.
When a strong acid is titrated with a strong base, the pH at the equivalence point
A.
is greater than 7.0.
B.
is equal to 7.0.
C.
is less than 7.0, but is not 3.5.
D.
is equal to the pKa of the acid.
E.
is equal to 3.5.


15.
Which one of the following is the best representation of the titration curve which will be obtained in the titration of a 0.10 M weak base with HCl of the same concentration?
A.
B.
C.
D.
E.


16.
Which of the following indicators would be the best to detect the equivalence point when 0.50 M benzoic acid (Ka = 6.6×10-5) is titrated with 0.50 M NaOH?
A.
bromphenol blue, pH range: 3.0-4.5
B.
bromcresol green, pH range: 3.8-5.4
C.
alizarin, pH range: 5.7-7.2
D.
phenolphthalein, pH range: 8.0-10.1
E.
alizarin yellow R, pH range: 10.0-12.0


17.
Calculate the solubility of strontium fluoride, SrF2, in pure water. Ksp = 2.6×10-9
A.
1.4 × 10-3 M
B.
3.4 × 10-4 M
C.
8.7 × 10-4 M
D.
5.l × 10-5 M
E.
1.0 × 10-5 M


18.
Calculate the solubility of lead(II) iodide, PbI2, in 0.025 M KI. Ksp(PbI2) = 7.9×10-9
A.
4.5 × 10-2 M
B.
2.8 × 10-2 M
C.
8.9 × 10-5 M
D.
5.0 × 10-5 M
E.
1.3 × 10-5 M


19.
A lab technician adds 0.20 mol of NaF to 1.00 L of 0.35 M cadmium nitrate, Cd(NO3)2. Which of the following statements is correct? Ksp = 6.44×10-3 for CdF2
A.
Cadmium fluoride precipitates until the solution is saturated.
B.
The solution is unsaturated and no precipitate forms.
C.
The solubility of cadmium fluoride is increased by the presence of additional fluoride ions.
D.
One must know Ksp for cadmium nitrate to make meaningful predictions on this system.
E.
The presence of NaF will raise the solubility of Cd(NO3)2.


20.
A solution is prepared by adding 4.50 mol of sodium hydroxide to 1.00 L of 1.00 M Co(NO3)2. What is the equilibrium concentration of cobalt ions? Kf = 5.0×109 for Co(OH)42-
A.
1.1 × 10-2 M
B.
1.4 × 10-5 M
C.
3.2 × 10-9 M
D.
2.0 × 10-10 M
E.
4.9 × 10-13 M


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