A 1.50 L buffer solution is 0.250 M in HF and 0.250 M in NaF.
Calculate the pH of the solution after the addition of 0.0500 moles of
solid NaOH. Assume no volume change upon the addition of base. The
K_{a} for HF is 3.5 × 10^{-4}.

A)3.63

B)3.34

C)3.46

D)2.89

E)3.57

Answer: E

Which of the following acids is the WEAKEST? The acid is followed by
its K_{a} value.

A)H COOH, 1.8 × 10^{-4}

B)HNO_{2}, 4.6 × 10^{-4}

C)HClO_{2}, 1.1 × 10^{-2}

D)HF, 3.5 × 10^{-4}

E)HCN, 4.9 × 10^{-10}

Answer E

Calculate the pOH in an aqueous solution with a pH of 7.85 at 25°C.

A)5.15

B)7.15

C)6.15

D)8.15

E)4.15

Answer C

The pH of an aqueous solution at 25.0°C is 10.66. What is the
molarity of H^{+} in this solution?

A)4.6 × 10^{10}

B)4.6 × 10^{-4}

C)2.2 × 10^{-11}

D)1.1 × 10^{-13}

E)3.3

Answer C

Consider a reaction that has a negative ΔH and a negative ΔS. Which of the following statements is TRUE?

A)This reaction will be nonspontaneous only at high temperatures.

B)This reaction will be nonspontaneous at all temperatures.

C)This reaction will be spontaneous at all temperatures.

D)This reaction will be spontaneous only at high temperatures.

E)It is not possible to determine without more information.

Answer A

Calculate the concentration of H_{3}O^{+} in a
solution that contains 5.5 × 10^{-5} M OH^{-} at 25°C.
Identify the solution as acidic, basic, or neutral.

A)5.5 × 10^{-10} M,neutral

B)1.8 × 10^{-10} M,basic

C)9.2 × 10^{-1} M, basic

D)1.8 × 10^{-10} M, acidic

E)9.2 × 10^{-1} M, acidic

Answer B

A buffer solution is 0.100 M in both
HC_{7}H_{5}O_{2} and
LiC_{7}H_{5}O_{2} and has a pH of 4.19. Which
of the following pH values would you expect from the addition of a
small amount of a dilute solution of a strong base?

A)5.69

B)4.49

C)3.69

D)3.89

E)There is not enough information to determine.

Answer B

Calculate the pH of a solution formed by mixing 150.0 mL of 0.10 M
HC_{7}H_{5}O_{2} with 100.0 mL of 0.30 M
NaC_{7}H_{5}O_{2}. The K_{a} for
HC_{7}H_{5}O_{2} is 6.5 × 10^{-5}.

A)4.31

B)9.69

C)4.19

D)10.51

E)4.49

Answer E

Calculate the pH of a buffer that is 0.158 M HClO and 0.099 M NaClO.
The K_{a} for HClO is 2.9 × 10^{-8}.

A)3.77

B)7.54

C)6.67

D)6.46

E)7.33

Answer E

A 100.0 mL sample of 0.18 M HClO_{4} is titrated with 0.27 M
LiOH. Determine the pH of the solution after the addition of 100.0 mL
of LiOH.

**A)0.87**

**B)12.6**
**5**

**C)12.95**

**D)13.13**

**E)1.35**

Answer B

Calculate the pH of a solution formed by mixing 250.0 mL of 0.15 M
HCHO_{2} with 100.0 mL of 0.20 M LiCHO_{2}. The
K_{a} for HCHO_{2} is 1.8 × 10^{-4}.

A)10.13

B)3.87

C)3.47

D)10.53

E)3.74

Answer C

Calculate the pH of a solution that contains 3.9 x
10^{-5} M H_{3}O^{+} at 25°C.

A)0.59

B)5.41

C)8.59

D)9.59

E)4.41

Answer E

Calculate the pH of a buffer that is 0.105 M
HC_{2}H_{3}O_{2} and 0.146 M
KC_{2}H_{3}O_{2}. The K_{a} for
HC_{2}H_{3}O_{2} is 1.8 × 10^{-5}.

A)9.11

B)9.26

C)4.60

D)4.89

E)4.74

Answer D

Calculate the pOH of a solution that contains 2.4 ×
10^{-5} M H_{3}O^{+} at 25°C.

A)2.40

B)9.38

C)4.62

D)5.62

E)8.38

Answer B

Which of the following acids will have the strongest conjugate base?

A)HClO_{4}

B)HCN

C)HNO_{3}

D)HCl

E)HI

Answer B

A 100.0 mL sample of 0.18 M HClO_{4} is titrated with 0.27 M
LiOH. Determine the pH of the solution after the addition of 30.0 mL
of LiOH.

A)1.12

B)2.86

C)1.21

D)2.00

E)0.86

Answer A

Determine the pH of a 0.023 M HNO_{3} solution.

A)12.36

B)2.30

C)1.64

D)2.49

E)3.68

Answer C

Calculate the hydroxide ion concentration in an aqueous solution with a pH of 9.85 at 25°C.

A)6.5 × 10^{-5} M

B)1.4 × 10^{-10} M

C)8.7 × 10^{-10} M

D)7.1 × 10^{-5} M

E)4.2 × 10^{-10} M

Answer D

Determine the [OH^{-}] concentration of a 0.123 M
Sr(OH)_{2} solution at 25°C.

A)0.0615 M

B)8.13 x 10^{-14} M

C)0.123 M

D)4.06 x 10^{-14} M

E)0.246 M

Answer E

Which of the following is a triprotic acid?

A)CCl_{4}

B)H_{3}PO_{4}

C)H_{2}SO_{4}

D)HI

E)HC_{2}H_{3}O_{2}

Answer B

Calculate the pOH of a solution that contains 7.8 x 10^{-6} M
OH^{-} at 25°C.

A)8.89

B)9.64

C)1.28

D)5.11

E)12.72

Answer D

If the pKa of HCHO_{2} is 3.74 and the pH of an
HCHO_{2}/NaCHO_{2} solution is 3.11, which of the
following is TRUE?

A)HCHO_{2}] << [NaCHO_{2}]

B)[HCHO_{2}] > [NaCHO_{2}]

C)[HCHO_{2}] = [NaCHO_{2}]

D)[HCHO_{2}] < [NaCHO_{2}]

E)It is not possible to make a buffer of this pH from
HCHO_{2} and NaCHO_{2}.

Answer B

Determine the molar solubility of Fe(OH)_{2} in pure water.
K_{sp} for Fe(OH)_{2})= 4.87 × 10^{-17}.

A)2.44 × 10^{-17} M

B)2.30 × 10^{-6} M

C)3.65 × 10^{-6} M

D)1.62 × 10^{-17} M

E)4.03 × 10^{-9} M

Answer B

Calculate the hydroxide ion concentration in an aqueous solution that
contains 3.50 × 10^{-4} M in hydronium ion.

A)2.86 × 10^{-11} M

B)2.86 × 10^{-3} M

C)3.50 × 10^{-11} M

D)2.86 × 10^{-10} M

Answer A

A 1.00 L buffer solution is 0.250 M in HF and 0.250 M in LiF.
Calculate the pH of the solution after the addition of 0.150 moles of
solid LiOH. Assume no volume change upon the addition of base. The
K_{a} for HF is 3.5 × 10^{-4}.

A)4.24

B)4.06

C)3.46

D)3.63

E)2.85

Answer B

Calculate the pH of a buffer that is 0.058 M HF and 0.058 M LiF. The
K_{a} for HF is 3.5 × 10^{-4}.

A)10.54

B)9.31

C)4.69

D)3.46

E)2.86

Answer D

Which of the following is a polyprotic acid?

**A)H _{2}SO_{4}**

**B)CCl _{4}**

**C)HCN**

**D)HI**

**E)HC _{2}H_{3}O_{2}**

Answer A

Place the following in order of increasing acid strength.

HBrO_{2} HBrO_{3} HBrO HBrO_{4}

_{A)HBrO2 < HBrO4 < HBrO < HBrO3}

_{B)HBrO < HBrO2 < HBrO3 < HBrO4}

_{C)HBrO4 < HBrO2 < HBrO3
< HBrO}

D)HBrO_{2} < HBrO_{3} < HBrO_{4} < HBrO

E)HBrO < HBrO_{4} < HBrO_{3} < HBrO_{2}

Answer B

What is the hydronium ion concentration of a 0.150 M hypochlorous
acid solution with k_{a}=3.5 x 10^{-8}. The equation
for the dissociation of hypochlorous acid is:

HOCl (aq)+ H_{2}O (l)--> <-- H_{3}O + (aq) +
OCl^{-} (aq)

A)7.2 × 10^{-4} M

B)1.9 × 10^{-4} M

C)7.2 × 10^{-5} M

D)2.8 × 10^{-5} M

Answer C

A 1.0 L buffer solution is 0.250 M
HC_{2}H_{3}O_{2} and 0.050 M
LiC_{2}H_{3}O_{2}. Which of the following
actions will destroy the buffer?

A)adding 0.050 moles of LiC_{2}H_{3}O_{2}

B)adding 0.050 moles of HC_{2}H_{3}O_{2}

C)adding 0.050 moles of NaOH

D)adding 0.050 moles of HCl

E)None of the above will destroy the buffer.

Answer D

Identify the weak diprotic acid.

A)HCOOH

B)CH_{3}COOH

C)H_{2}CO_{3}

D)H_{3}PO_{4}

E)H_{2}SO_{4}

Answer C

Determine the K_{a} of an acid whose 0.294 M solution has a
pH of 2.80.

A)5.4 × 10^{-3}

B)8.5 × 10^{-6}

C)1.2 × 10^{-5}

D)4.9 × 10^{-7}

E)2.7

Answer B

Identify the weakest acid.

A)HF

B)HI

C)HCl

D)HBr

E)not enough information is available

Answer A

Calculate the molarity of hydroxide ion in an aqueous solution that has a pOH of 5.00.

A)9.0 × 10^{-14}

B)5.0 × 10^{-14}

C)9.00

D)1.0 × 10^{-9}

E)1.0 × 10^{-5}

Answer E

Calculate the pH of a buffer that is 0.040 M HF and 0.020 M LiF. The
K_{a} for HF is 3.5 × 10^{-4}.

A)3.16

B)3.76

C)4.86

D)2.06

E)3.46

Answer A

A 100.0 mL sample of 0.10 M Ca(OH)_{2} is titrated with 0.10
M HBr. Determine the pH of the solution after the addition of 400.0 mL HBr.

A)2.11

B)1.22

C)1.00

D)1.40

E)1.30

Answer D

Identify the weak diprotic acid.

A)H_{3}PO_{4}

B)HClO_{4}

C)H_{2}SO_{3}

D)H_{2}SO_{4}

E)HNO_{3}

Answer C

You wish to prepare an HC_{2}H_{3}O_{2}
buffer with a pH of 4.24. If the pK_{a} of is 4.74, what ratio
of C_{2}H_{3}O_{2}
^{-}/HC_{2}H_{3}O_{2} must you use?

A)0.32

B)2.8

C)0.10

D)0.50

E)2.0

Answer A

A 7.0 × 10^{-3} M aqueous solution of Ca(OH)_{2} at
25.0°C has a pH of ________.

A)1.85

B)12.15

C)11.85

D)1.4 × 10^{-2}

E)7.1 × 10^{-13}

Answer B

A 100.0 mL sample of 0.180 M HClO_{4} is titrated with 0.270
M LiOH. Determine the pH of the solution after the addition of 75.0 mL
of LiOH.

A)2.65

B)1.89

C)12.1

D)13.06

E)11.35

Answer C

Calculate the pH for an aqueous solution of pyridine that contains
2.15 x 10^{-4} M hydroxide ion.

A)3.67

B)2.15 × 10^{-4}

C)10.33

D)4.65 × 10^{-11}

Answer C

Determine the molar solubility of BaF_{2} in a solution
containing 0.0750 M LiF. K_{sp} (BaF_{2}) = 1.7 × 10^{-6}.

A)8.5 × 10^{-7} M

B)3.0 × 10^{-4} M

C)1.2 × 10^{-2} M

D)2.3 × 10^{-5} M

E)0.0750 M

Answer B

Determine the pOH of a 0.00598 M HClO_{4} solution.

A)11.777

B)2.223

C)6.434

D)7.566

E)3.558

Answer A

A 100.0 mL sample of 0.20 M HF is titrated with 0.10 M KOH. Determine
the pH of the solution after the addition of 200.0 mL of KOH. The
K_{a} of HF is 3.5 × 10^{-4}.

A)9.62

B)7.00

C)3.46

D)10.54

E)8.14

Answer E

The molar solubility of Ag_{2}S is 1.26 × 10^{-16} M
in pure water. Calculate the K_{sp} for Ag_{2}S.

A)6.81 × 10^{-63}

B)3.78 × 10^{-12}

C)8.00 × 10^{-48}

D)1.12 × 10^{-8}

E)1.59 × 10^{-32}

Answer C

Calculate the pH of a solution formed by mixing 100.0 mL of 0.20 M
HClO with 200.0 mL of 0.30 M KClO. The K_{a} for HClO is 2.9 × 10^{-8}.

A)7.06

B)6.46

C)5.99

D)8.01

E)7.54

Answer D

A 100.0 mL sample of 0.18 M HClO_{4} is titrated with 0.27 M
LiOH. Determine the pH of the solution after the addition of 66.67 mL
of LiOH (this is the equivalence point).

A)7.00

B)2.76

C)11.24

D)13.03

E)0.97

Answer A

Calculate the pH of a buffer that is 0.225 M
HC_{2}H_{3}O_{2} and 0.162 M
KC_{2}H_{3}O_{2}. The K_{a} for
HC_{2}H_{3}O_{2} is 1.8 × 10^{-5}.

A)4.74

B)4.89

C)9.26

D)9.11

E)4.60

Answer E

What is the hydronium ion concentration of a 0.500 M acetic acid
solution with *K*
_{a} = 1.8 × 10^{-5}? The equation for the
dissociation of acetic acid is:

CH_{3}CO_{2}H(aq)+H_{2}O (l) <-- --->
H_{3}O^{+}(aq)+ CH_{3}CO_{2}
^{-}(aq)

A)3.0 × 10^{-2} M

B)3.0 × 10^{-3} M

C)4.2 × 10^{-3} M

D)4.2 × 10^{-2} M

Answer B

Calculate the hydronium ion concentration in an aqueous solution that
contains 2.50 × 10^{-6} M in hydroxide ion.

A)4.00 × 10^{-7} M

B)4.00 × 10^{-8} M

C)4.00 × 10^{-9} M

D)5.00 × 10^{-9} M

Answer C