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WorksheetspH,pOH, Ka &Kb Test Review
Total questions: 112
Worksheet time: 2hrs 18mins
What is the pH of an acidic solution of 0.0025M HCl
4.60
5.0
2.6
7
What is the pH of a solution where the [OH-] is 7.30 x 10-2 M?
1.14
2.0
12.9
7.3
What is the [H+] if the pH is 4.0?
1.0 x 10-10 M
1.0 x 10-4 M
1.0 x 10-14 M
1.0 x 10-7 M
what is the [H+] is the [OH-] is 2.43x10-9
4.11x10-6
4.12x10-6
4.1x10-6
4.0x10-6
What is the [OH-] if the pH is 4.9?
7.94 x 10-10 M
1.0 x 10-4 M
7.94 x 10-14 M
4.9 x 10-10 M
The lower the pH, the greater the concentration of :
OH-
H+
The greater the pOH, the smaller the concentration of
OH-
H+
What is the pOH of a 0.050M the base Ca(OH)2 solution
11
13
14
1.0
calculate the % ionization of a 0.050 M solution of a base with the Kb = 4.2x10-2
2.9
0.029
0.084
2.1
calculate the [OH-] of a 0.50M solution of NH3 that has a % ionization of 4.6%
0.023M
2.3M
3.3M
9.2M
Calculate the Kb of a solution that has a pKb of 4.2
0.62
6.3x10-5
9.8
4.2
calculate the pKb of solution with a pKa of 6.9
7.1
6.5
14
9.6
calculate the Ka of a solution with a pKb of 3.38
3.38x10-11
6.76x10-11
2.40x10-11
2.39x10-11
For a solution at 25oC, pH + pOH =
7
14
1.0 x 10-14
-log (1.0 x 10 -14)
If the pH of a solution is 4.0, what is the pOH?
4.0
10.0
1.0 x 10 -4
cannot be determined from the information
If the [H3O+] of a solution is 1 x 10-3 M, the pH is
11
-3
3
1
If the pH of a solution is 8 the [H3O+] is
1.0 x 106 M
8.0 x 101 M
1.0 x 108 M
1.0 x 10-8 M
The pH of a solution is 8.43. What is the [H3O+] concentration?
3.7 x 10 -9
1.0 x 10-8.43
2.7 x 10-6
1.0 x 10-14
What is the numerical value of Kw, the water dissociation constant?
14.0 x 10-1
7.0 x 10-2
2.0 x 10-7
1.0 x 10-14
If the [H3O+] of a solution is 9.3 x 10-3 M, the pOH of the solution will be
2.03
1.02
11.97
12.98
When a water molecule loses a hydrogen ion, or proton, it becomes ___
a hydronium ion, H3O+
a hydroxide ion, OH-
a hydronium ion, OH-
a hydroxide ion, H3O+
If a solution has a pOH of 3.7, the [OH-] of the solution is
5.0 x 10-11
2.0 x 10-4
10.3
14
Oranges have a [H3O+] of 1.7 x 10-2 M. Their pOH is
1.77
12.23
10.91
3.09
Find the pH of a solution with [OH-] = 8.41 x 10-4.
3.08
10.92
9.88
11.23
The equilibrium constant for the reaction
A– + H+ ↔ HA
is called
Ka
Kb
1/Ka
1/Kb
Kw
A
B
C
A
B
C
A
B
In which of the following aqueous solutions does the weak acid exhibit the highest percentge of ionization?
.01 M HC2H3O2 . (Ka 1.8 x 10 -5)
.01 M HNO2 . ( Ka =4.5 x 10 -4)
.01 M HClO . (Ka= 3.0 x 10 -8)
.01 M HF (Ka= 6.8 x 10 -4)
A- is a weak base. Which equilibrium corresponds to the equilibrium constant Ka for HA?
HA (aq) + H2O (l) <---> H2A+ (aq) + OH- (aq)
A- (aq) + H3O+ (aq) <---> HA (aq) + H2O (l)
HA (aq) + H2O (l) <---> H3O+ (aq) + A- (aq)
A- (aq) + H2O (l) <---> HA (aq) + OH- (aq)
A- (aq) + OH- (aq) <---> HOA2- (aq)
Using the data in the table, which of the conjugate bases below is the strongest base?
OAc-
CHO2-
ClO-
F-
OAc- and CHO2-
Using the data in the table, which of the conjugate acids below is the strongest acid?
HClO
HCO3-
H2S
NH3CH3+
H2S and HClO
Z- is a weak base. An aqueous solution of NaZ is prepared by dissolving 0.350 mol of NaZ in sufficient water to yield 1.0 L of solution. The pH of the solution was 8.93 at 25.0 0C. What is the Kb of the solution?
1.2 x 10-5
6.9 x 10 -9
2.1 x 10 -10
2.8 x 10 -12
i. H2CO3 Ka = 4.3 x 10-7
ii. NH4+ Ka = 5.6 x 10-10
iii. HCNO Ka = 3.5 x 10-4
A(n) ______ is a substance with a pH less than 7.
acid
alkaline
base
buffer
Which of the following are the conjugate bases of HSO4–, CH3OH, and H3O+, respectively?
SO42–, CH2OH–, and OH–
CH3O–, SO42–, and H2O
SO42–, CH3O–, and H2O
SO42–, CH2OH–, and H2O
Which of the following is the strongest weak acid?
HF (pKa = 3.17)
HCO3– (pKa = 10.32)
H2PO4– (pKa = 7.18)
NH4+ (pKa = 9.20)
Which of the following produces the strongest conjugate base?
HF (pKa = 3.17)
HCO3– (pKa = 10.32)
H2PO4– (pKa = 7.18)
NH4+ (pKa = 9.20)
The value of Ka for HSO4– is 1 × 10–2. What is the value of Kb for SO42–?
1 × 10–12
1 × 10–8
1 × 10–2
1 × 102
A 1-molar solution of a very weak monoprotic acid has a pH of 5. What is the value of Ka for the acid?
1 × 10–10
1 × 10–7
1 × 10–5
1 × 10–2
If [H3O+] in an aqueous solution is 7.5 × 10–9 M, what is the [OH–]?
6.4 × 10–5 M
3.8 × 10–5 M
7.5 × 10–5 M
1.3 × 10–5 M
Which species has a Ka of 5.6 × 10–10 if NH3 has a Kb of 1.8 × 10–5?
H
NH2–
NH4+
H2O
Select ALL of the strong acids.
HClO4
HNO2
HF
HI
HNO3
True or False? The stronger the acid, the larger the value of the Ka.
True
False
What is the pH of 0.45 M HCN if it has a pKa of 9.21?
4.8
3.1
5.8
1.7
Which represents an acid with the smallest Ka value?
HX
HY
HZ
Which acid would have the smallest pH value?
HX
HY
HZ
strong acids have a ____Ka and a ____pKa
low...high
high... low
high....high
low...low
A strong acid produces a ___conjugate base
weak
strong
Which of the following is the strongest acid
pKa= 12
pKa=3
an acid whose conj base has pKb= 1
an acid whose conjugate base has pKb=13
HCl + KOH --> H2O + KCl
If a student uses 25.0 mL of a 0.5M solution of KOH, what is the molarity of the acid if 15.0mL of acid neutralized?
What is the endpoint of a titration
Where the amount of acid and base are equal as shown by a color change
Where there is no base
When the volume of base in the burette is used up
When there is no acid
A solution contains 0.04 M of a weak acid. Calculate the pH of the solution knowing that the Ka for the acid is 1.6 x 10-7
It is not possible to solve if the identity of the acid is not known
4.1
4.9
Because the Ka is very small, the pH is close to neutral (about 6)
What is the conjugate acid of CO3-2?
CO2-2
HCO22-2
H2CO3
HCO3-1
A
B
C
A
B
C
D
E
A
B
C
A
B
A 50.0 mL sample of an acid, HA, of unknown molarity is titrated, and the pH of the resulting solution is measured with a pH meter and graphed as a function of the volume of 0.100 M NaOH added.
At point R in the titration, which of the following species has the highest concentration?
HA
A-
H3O+
OH-
A solution of a weak monoprotic acid is titrated with a solution of a strong base, KOH. Consider the points labeled (A) through (E) on the titration curve
that results, as shown below.
The point at which the concentrations of the weak acid and its conjugate base are approximately equal is
A
B
C
D
E
The graph above shows the titration curve that resulted when a sample of 0.1 M monoprotic acid was titrated with a solution of NaOH. Based on the graph, the pKa of the acid is closest to
3.0
4.0
6.0
8.0
12.0
A student performs an acid-base titration and plots the experimental results in the graph above. Which of the following statements best explains the experimental findings?
A strong acid was titrated with a strong base, as evidenced by the equivalence point at pH = 7.
A strong acid was titrated with a strong base, as evidenced by the equivalence point at pH > 7.
A weak acid was titrated with a strong base, as evidenced by the equivalence point at pH > 7.
A weak acid was titrated with a weak base, as evidenced by the equivalence point at pH approximately 7.
NaOH(aq) + HCl(aq) → NaCl(aq) + H2O(l)
To determine the concentration of a NaOH(aq) solution, a student titrated a 50. mL sample with 0.10 M HCl(aq) . The reaction is represented by the equation above. The titration is monitored using a pH meter, and the experimental results are plotted in the graph below.
One student titrated the NaOH(aq) with 1.0 M HCl(aq) instead of 0.10 M HCl(aq) . How would the student’s titration curve differ from the original curve?
The initial pH would be 11 instead of 13.
The pH at the equivalence point would be 5 instead of 7.
The pH far beyond the equivalence point would be higher than in the original curve.
The pH far beyond the equivalence point would be lower than in the original curve.
A 50.0 mL sample of an acid, HA, of unknown molarity is titrated, and the pH of the resulting solution is measured with a pH meter and graphed as a function of the volume of 0.100 M NaOH added.
Which of the following is the best particulate representation of the species (other than H2O) that are present in significant concentrations in the solution at point U in the titration?
Which of the following would be the SAME for equal volumes of 1.0 M HCl and
1.0 M HF?
pH
percent ionization
conductivity
moles of NaOH needed to neutralize acid sample
Which of the following gives the best estimate for the pH of a 1 × 10⁻⁵ M HClO₄ (aq) solution at 25°C?
pH = 1.0, because HClO₄ is a strong acid
pH = 5.0, because HClO₄ is a strong acid
pH = 7.0, because HClO₄ is a strong base
pH = 9.0, because HClO₄ is a strong base
Which acid below has the WEAKEST conjugate base?
Hydrofluoric acid, HF
(Ka = 7.2 x 10⁻⁴)
Acetic Acid, CH₃COOH
(Ka = 1.8 x 10⁻⁵)
Hydrocyanic acid, HCN
(Ka = 6.2 x 10⁻¹⁰)
Formic acid, HCOOH
(Ka = 1.8 x 10 ⁻⁴)
Which of the following gives the best estimate for the pH of a 5 × 10⁻⁴ M Sr(OH)₂ (aq) solution at 25°C?
pH = 3.0 because Sr(OH)₂ is a strong acid.
pH = 5.0 because Sr(OH)₂ is a weak acid.
pH = 9.0 because Sr(OH)₂ is a weak base.
pH = 11.0 because Sr(OH)₂ is a strong base.
Which one of the following is the weakest acid?
HF (Ka = 6.8 x 10⁻⁴)
HC₂H₃O₂ (Ka = 1.8 x 10⁻⁵)
HNO₂ (Ka = 4.5 x 10⁻⁴)
HClO (Ka = 3.0 x 10⁻⁸)
Of the following, __________ is a weak acid.
CH₃NH₂
HF
HClO₄
HCl
Which solution below has the highest concentration of hydroxide ions?
pH = 3.21
pH = 9.82
pH = 7.93
pH = 12.59
HA is a weak acid. Which equilibrium reaction corresponds to the equilibrium constant Kb for A-?
HA (aq) + H2O (l) ⇌ H2A+ (aq) + OH-(aq)
A- (aq) + H3O+ (aq) ⇌ HA (aq) + H2O (l)
HA (aq) + OH- (aq) ⇌ H2O (l) + H+ (aq)
A- (aq) + H2O (l) ⇌ HA (aq) + OH- (aq)
A- (aq) + OH- (aq) ⇌ HOA2- (aq)
Using the data in the table, which of the conjugate bases below is the weakest base?
OAc-
C7H5O2-
NO2-
F-
OAc- and C7H5O2-
Using the data in the table, which of the conjugate bases below is the strongest base?
OAc-
CHO2-
ClO-
F-
OAc- and CHO2-
Using the data in the table, which of the conjugate acids below is the strongest acid?
HClO
HCO3-
H2S
NH3CH3+
H2S and HClO
Using the data in the table, which of the conjugate acids below is the weakest acid?
HClO
HCO3-
H2S
NH3CH3+
H2S and HClO
Z- is a weak base. An aqueous solution of NaZ is prepared by dissolving 0.350 mol of NaZ in sufficient water to yield 1.0 L of solution. The pH of the solution was 8.93 at 25.0 0C. What is the Kb of the solution?
1.2 x 10-5
6.9 x 10-9
2.1 x 10-10
2.8 x 10-12
Z- is a weak base. An aqueous solution of NaZ is prepared by dissolving 0.350 mol of NaZ in sufficient water to yield 1.0 L of solution. The pH of the solution was 8.93 at 25.0 0C. What is the Kb of the solution?
1.2 x 10-5
6.9 x 10-9
2.1 x 10-10
2.8 x 10-12
Acetic cid (HC2H3O2) is a weak monoprotic acid. Calculate the pH of a 0.20 M acetic acid solution. Ka = 1.8x10-5 for acetic acid.
.698
2.72
11.28
None of the answers are correct
Which of the following would be a weak base?
In which of the following reactions does H2PO4- act as an acid?
H3PO4 + H2O ⇌ H3O+ + H2PO4-
H2PO4- + H2O ⇌ H3O+ + HPO42-
H2PO4- + OH- ⇌ H3PO4 + O2-
The ion cannot act as an acid
What is the conjugate base of HSO4-
H2SO4
SO42-
H2SO4+
HSO42-
Calculate the pH of a 0.500 M NH3 solution. The Kb of ammonia is 1.77x 10-5.
12.58
2.98
11.47
10.69
The Ka for gallic acid is 4.57 x 10-3. What is the Kb for gallate ion (its conjugate base)?
4.57 x 10-3
5.43 x 10-5
2.19 x 10-12
7.81 x 10-6
The Ka for HF is 7.0 x 10-4. What is the Kb for F-?
1.4 x 10-11
2.0 x 10-8
7.0 x 10-18
7.0 x 10-4
1.4 x 103
Which of the following is closest to the pKa for an acid, HA, with Ka = 4.5 x 10-11 M.
11.45
4.5
10.55
15.5
Which acid produces the strongest conjugate base?
HClO4 (Ka= 1.0 x 107)
HCN (Ka= 4.0 x 10-10)
H3PO4 (Ka= 7.5 x 10-3)
H2CO3 (Ka = 4.2 x 10-7)
What is the pOH of a solution where the [OH–] is 7.3 × 10–2 M?
-1.14
2.0
1.14
7.3
Which of the following produces the strongest conjugate base?
CH3COOH (Ka = 1.8 × 10–5)
HF (Ka = 6.5 × 10–4)
HCN (Ka = 6.3 × 10–10)
HClO (Ka = 3.0 × 10–8)
Which of the following is the strongest weak acid?
HF (pKa = 3.17)
HCO3– (pKa = 10.32)
H2PO4– (pKa = 7.18)
NH4+ (pKa = 9.20)
The value of Ka for HSO4– is 1 × 10–2. What is the value of Kb for SO42–?
1 × 10–12
1 × 10–8
1 × 10–2
1 × 102
The initial concentration of a weak monoprotic acid HA is 0.20M and the equilibrium concentration of H+ ions is 0.0019M. Calculate the Ka value for the weak acid.
1.8x10-5
1.8x10-15
0.0019
5.56x10-10
Isobutlyamine is a weak base. If the initial concentration is 0.55M and the equilibrium concentration of OH- ions is 0.0040M, calculate the Kb value for isobutylamine.
.055
4.0x10-3
1.6x10-5
3.1x10-4
2.9 x 10-5
Ammonia is a weak base. Calculate the pH of a solution with concentration is 0.150M. Kb = 1.7x10-5
2.80
11.20
2.37
5.59
8.41
the following equation represents the equilibrium reaction between weak base, B, with water :
B(aq) + H2O(l) ⇌ BH+(aq) + OH-(aq)
The equilibrium constant for this reaction is represented by Kb . Which of the following equation represents expression of equilibrium constant, Kb?
i. H2CO3 Ka = 4.3 x 10-7
ii. NH4+ Ka = 5.6 x 10-10
iii. HCNO Ka = 3.5 x 10-4
Equal moles of the indicated acids are dissolved in the amounts of water shown in the beakers below. In which solution will the percent ionization of the acid be the lowest?
Beaker A
Beaker B
Beaker C
Impossible to tell from the information given.
Z-1 is a weak base. An aqueous solution of Naz is prepared by dissolving 0.350 mol of NaZ in sufficient water to yield 1.0 L of solution. The pH of the solution was 8.93 at 25.0 0C. What is the Kb of the solution?
1.2 x 10-5
6.9 x 10-9
2.1 x 10-10
2.8 x 10-12
Given 0.10 M solutions of the four weak acids below all with 0.10 M concentration, which will have the greatest percent ionization?
HF (Ka = 7.2 x 10-4)
HNO2 (Ka = 4.0 x 10-4)
HCO2H (Ka = 1.8 x 10-4)
HC3H5O3 (Ka = 1.4 x 10-4)
HF because its Ka is the largest.
HF because its molar mass is the smallest.
HC3H5O3 because its Ka is the smallest.
HC3H5O3 because its molar mass is the greatest.
Which of the following represents an acid with the lowest pH? Assume the solutions are the same concentration.
