Question 1

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

Accepted Answer

A)  1.4 × 10- 2 
B)  12.15 
C)  7.1 × 10- 13 
D)  11.85 
E)  1.85 
A)  1.4 × 10- 2 
B)  12.15 
C)  7.1 × 10- 13 
D)  11.85 
E)  1.85

Question 2

An aqueous solution contains 0.10 M NaOH. The solution is _.

Accepted Answer

A)  highly colored 
B)  basic 
C)  acidic 
D)  very dilute 
E)  neutral 
A)  highly colored 
B)  basic 
C)  acidic 
D)  very dilute 
E)  neutral

Question 3

Ammonia is a .

Accepted Answer

A)  weak acid 
B)  strong acid 
C)  strong base 
D)  salt 
E)  weak base 
A)  weak acid 
B)  strong acid 
C)  strong base 
D)  salt 
E)  weak base

Question 4

A 0.15 M aqueous solution of the weak acid HA at 25.0 °C has a pH of 5.35. The value of Ka for HA is .

Accepted Answer

A)  7.1 × 10- 9 
B)  1.4 × 10- 10 
C)  3.3 × 104 
D)  3.0 × 10- 5 
E)  1.8 × 10- 5 
A)  7.1 × 10- 9 
B)  1.4 × 10- 10 
C)  3.3 × 104 
D)  3.0 × 10- 5 
E)  1.8 × 10- 5

Question 5

The acid- dissociation constants of phosphoric acid (H3PO4) are Ka1 = 7.5 × 10- 3, Ka2 = 6.2 × 10- 8, and Ka3 = 4.2 × 10- 13 at 25.0 °C. What is the molar concentration of phosphate ion in a 2.5 M aqueous solution of phosphoric acid?

Accepted Answer

A)  0.13 
B)  2.5 × 10- 5 
C)  2.0 × 10- 19 
D)  9.1 × 10- 5 
E)  8.2 × 10- 9 
A)  0.13 
B)  2.5 × 10- 5 
C)  2.0 × 10- 19 
D)  9.1 × 10- 5 
E)  8.2 × 10- 9

Question 6

A substance that is capable of acting as both an acid and as a base is .

Accepted Answer

A)  conjugated 
B)  amphoteric 
C)  miscible 
D)  autosomal 
E)  saturated 
A)  conjugated 
B)  amphoteric 
C)  miscible 
D)  autosomal 
E)  saturated

Question 7

A solution of formic acid is 3.0% dissociated at 25.0 oC. What is the original concentration (in M) of the formic acid solution? The Ka at 25.0 oC for formic acid is 1.8 × 10- 4.

Accepted Answer

Question 8

Calculate the pH of 0.726 M anilinium hydrochloride (C6H5NH3Cl) solution in water, given that Kb for aniline is 3.83 × 10- 4.

Accepted Answer

A)  12.2 
B)  12.4 
C)  5.36 
D)  8.64 
E)  1.77 
A)  12.2 
B)  12.4 
C)  5.36 
D)  8.64 
E)  1.77

Question 9

According to the Arrhenius concept, an acid is a substance that .

Accepted Answer

A)  causes an increase in the concentration of H+ in aqueous solutions 
B)  tastes bitter 
C)  can accept a pair of electrons to form a coordinate covalent bond 
D)  is capable of donating one or more H+ 
E)  reacts with the solvent to form the cation formed by autoionization of that solvent 
A)  causes an increase in the concentration of H+ in aqueous solutions 
B)  tastes bitter 
C)  can accept a pair of electrons to form a coordinate covalent bond 
D)  is capable of donating one or more H+ 
E)  reacts with the solvent to form the cation formed by autoionization of that solvent

Question 10

What is the pH of an aqueous solution at 25.0 °C in which [H+] is 0.00250 M?

Accepted Answer

A)  3.40 
B)  2.60 
C)  - 2.60 
D)  2.25 
E)  - 3.40 
A)  3.40 
B)  2.60 
C)  - 2.60 
D)  2.25 
E)  - 3.40

Question 11

What is the conjugate acid of NH3?

Accepted Answer

A)  NH3+  
B)  NH4OH 
C)  NH3  
D)  NH4+  
E)  NH2+ 
A)  NH3+  
B)  NH4OH 
C)  NH3  
D)  NH4+  
E)  NH2+

Question 12

HZ is a weak acid. An aqueous solution of HZ is prepared by dissolving 0.020 mol of HZ in sufficient water to yield 1.0 L of solution. The pH of the solution was 4.93 at 25.0 °C. The Ka of HZ is .

Accepted Answer

A)  1.4 × 10- 10 
B)  2.8 × 10- 12 
C)  1.2 × 10- 5 
D)  9.9 × 10- 2 
E)  6.9 × 10- 9 
A)  1.4 × 10- 10 
B)  2.8 × 10- 12 
C)  1.2 × 10- 5 
D)  9.9 × 10- 2 
E)  6.9 × 10- 9

Question 13

Ka for HX is 7.5 × 10- 12. What is the pH of a 0.15 M aqueous solution of NaX?

Accepted Answer

A)  8.0 
B)  12 
C)  7.9 
D)  6.0 
E)  1.9 
A)  8.0 
B)  12 
C)  7.9 
D)  6.0 
E)  1.9

Question 14

The acid- dissociation constant at 25.0 °C for hypochlorous acid (HClO) is 3.0 × 10- 8. At equilibrium, the molarity of H3O+ in a 0.010 M solution of HClO is .

Accepted Answer

A)  2.00 
B)  0.010 
C)  1.7 × 10- 5 
D)  5.8 × 10- 10 
E)  4.76 
A)  2.00 
B)  0.010 
C)  1.7 × 10- 5 
D)  5.8 × 10- 10 
E)  4.76

Question 15

Which one of the following is the weakest acid?

Accepted Answer

A)  HCN (Ka = 4.9 × 10- 10) 
B)  Acetic acid (Ka = 1.8 × 10- 5) 
C)  HF (Ka = 6.8 × 10- 4) 
D)  HNO2 (Ka = 4.5 × 10- 4) 
E)  HClO (Ka = 3.0 × 10- 8) 
A)  HCN (Ka = 4.9 × 10- 10) 
B)  Acetic acid (Ka = 1.8 × 10- 5) 
C)  HF (Ka = 6.8 × 10- 4) 
D)  HNO2 (Ka = 4.5 × 10- 4) 
E)  HClO (Ka = 3.0 × 10- 8)

Question 16

The molar concentration of hydronium ion in pure water at 25°C is .

Accepted Answer

A)  1.00 
B)  1.0 × 10- 14 
C)  0.00 
D)  7.00 
E)  1.0 × 10- 7 
A)  1.00 
B)  1.0 × 10- 14 
C)  0.00 
D)  7.00 
E)  1.0 × 10- 7

Question 17

A 0.0035- M aqueous solution of a particular compound has pH = 2.46. The compound is
)

Accepted Answer

A)  a weak acid 
B)  a strong base 
C)  a salt 
D)  a strong acid 
E)  a weak base 
A)  a weak acid 
B)  a strong base 
C)  a salt 
D)  a strong acid 
E)  a weak base

Question 18

The base- dissociation constant of ethylamine (C2H5NH2) is 6.4 × 10- 4 at 25.0 °C. The of [H+] in a 1.6 × 10- 2 M solution of ethylamine is M.

Accepted Answer

A)  3.2 × 10- 3 
B)  2.9 × 10- 3 
C)  11.46 
D)  3.1 × 10- 12 
E)  3.5 × 10- 12 
A)  3.2 × 10- 3 
B)  2.9 × 10- 3 
C)  11.46 
D)  3.1 × 10- 12 
E)  3.5 × 10- 12

Question 19

The pH of a 0.55 M aqueous solution of hypobromous acid, HBrO, at 25.0 °C is 4.48. What is the value of Ka for HBrO?

Accepted Answer

A)  3.3 × 10- 5  
B)  6.0 × 10- 5  
C)  1.1 × 10- 9  
D)  3.0 × 104  
E)  2.0 × 10- 9 
A)  3.3 × 10- 5  
B)  6.0 × 10- 5  
C)  1.1 × 10- 9  
D)  3.0 × 104  
E)  2.0 × 10- 9

Question 20

Ka for HCN is 4.9 × 10- 10. What is the pH of a 0.068 M aqueous solution of sodium cyanide?

Accepted Answer

A)  0.74 
B)  2.9 
C)  7.0 
D)  13 
E)  11 
A)  0.74 
B)  2.9 
C)  7.0 
D)  13 
E)  11

Exam 16: Acid-Base Equilibria

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

An aqueous solution contains 0.10 M NaOH. The solution is _.

Ammonia is a .

A 0.15 M aqueous solution of the weak acid HA at 25.0 °C has a pH of 5.35. The value of Ka for HA is .

The acid- dissociation constants of phosphoric acid (H3PO4) are Ka1 = 7.5 × 10- 3, Ka2 = 6.2 × 10- 8, and Ka3 = 4.2 × 10- 13 at 25.0 °C. What is the molar concentration of phosphate ion in a 2.5 M aqueous solution of phosphoric acid?

A substance that is capable of acting as both an acid and as a base is .

A solution of formic acid is 3.0% dissociated at 25.0 oC. What is the original concentration (in M) of the formic acid solution? The Ka at 25.0 oC for formic acid is 1.8 × 10- 4.

Calculate the pH of 0.726 M anilinium hydrochloride (C6H5NH3Cl) solution in water, given that Kb for aniline is 3.83 × 10- 4.

According to the Arrhenius concept, an acid is a substance that .

What is the pH of an aqueous solution at 25.0 °C in which [H+] is 0.00250 M?

What is the conjugate acid of NH3?

HZ is a weak acid. An aqueous solution of HZ is prepared by dissolving 0.020 mol of HZ in sufficient water to yield 1.0 L of solution. The pH of the solution was 4.93 at 25.0 °C. The Ka of HZ is .

Ka for HX is 7.5 × 10- 12. What is the pH of a 0.15 M aqueous solution of NaX?

The acid- dissociation constant at 25.0 °C for hypochlorous acid (HClO) is 3.0 × 10- 8. At equilibrium, the molarity of H3O+ in a 0.010 M solution of HClO is .

Which one of the following is the weakest acid?

The molar concentration of hydronium ion in pure water at 25°C is .

A 0.0035- M aqueous solution of a particular compound has pH = 2.46. The compound is )

The base- dissociation constant of ethylamine (C2H5NH2) is 6.4 × 10- 4 at 25.0 °C. The of [H+] in a 1.6 × 10- 2 M solution of ethylamine is M.

The pH of a 0.55 M aqueous solution of hypobromous acid, HBrO, at 25.0 °C is 4.48. What is the value of Ka for HBrO?

Ka for HCN is 4.9 × 10- 10. What is the pH of a 0.068 M aqueous solution of sodium cyanide?

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

A 0.15 M aqueous solution of the weak acid HA at 25.0 °C has a pH of 5.35. The value of K_afor HA is .

The acid- dissociation constants of phosphoric acid (H₃PO₄) are K_a1= 7.5 × 10^-³, K_a2= 6.2 × 10^-⁸, and K_a3= 4.2 × 10^-¹³at 25.0 °C. What is the molar concentration of phosphate ion in a 2.5 M aqueous solution of phosphoric acid?

A solution of formic acid is 3.0% dissociated at 25.0 ^oC. What is the original concentration (in M) of the formic acid solution? The K_aat 25.0 ^oC for formic acid is 1.8 × 10^-⁴.

Calculate the pH of 0.726 M anilinium hydrochloride (C₆H₅NH₃Cl) solution in water, given that K_bfor aniline is 3.83 × 10^-⁴.

What is the pH of an aqueous solution at 25.0 °C in which [H⁺] is 0.00250 M?

What is the conjugate acid of NH₃?

HZ is a weak acid. An aqueous solution of HZ is prepared by dissolving 0.020 mol of HZ in sufficient water to yield 1.0 L of solution. The pH of the solution was 4.93 at 25.0 °C. The K_aof HZ is .

K_afor HX is 7.5 × 10^-¹². What is the pH of a 0.15 M aqueous solution of NaX?

The acid- dissociation constant at 25.0 °C for hypochlorous acid (HClO) is 3.0 × 10^-⁸. At equilibrium, the molarity of H₃O⁺in a 0.010 M solution of HClO is .

The base- dissociation constant of ethylamine (C₂H₅NH₂) is 6.4 × 10^-⁴at 25.0 °C. The of [H⁺] in a 1.6 × 10^-²M solution of ethylamine is M.

The pH of a 0.55 M aqueous solution of hypobromous acid, HBrO, at 25.0 °C is 4.48. What is the value of K_afor HBrO?

K_afor HCN is 4.9 × 10^-¹⁰. What is the pH of a 0.068 M aqueous solution of sodium cyanide?