Question 1

The acid-dissociation constant of hydrocyanic acid (HCN)at 25.0 °C is 4.9 × 10-10. What is the pH of an aqueous solution of 0.050 M sodium cyanide (NaCN)?

Accepted Answer

A) 11.00 
B) 3.00 
C) 1.0 × 10-3 
D) 9.9 × 10-12 
E) 2.5 × 10-11 
A) 11.00 
B) 3.00 
C) 1.0 × 10-3 
D) 9.9 × 10-12 
E) 2.5 × 10-11

Question 2

Of the following substances, an aqueous solution of ________ will form basic solutions. NH4Cl Cu(NO3)2 K2CO3 NaF

Accepted Answer

A) NH4Cl, Cu(NO3)2 
B) K2CO3, NH4Cl 
C) NaF only 
D) NaF, K2CO3 
E) NH4Cl only 
A) NH4Cl, Cu(NO3)2 
B) K2CO3, NH4Cl 
C) NaF only 
D) NaF, K2CO3 
E) NH4Cl only

Question 3

Which solution below has the highest concentration of hydroxide ions?

Accepted Answer

A) pH = 12.5 
B) pH = 11 
C) pH = 8.3 
D) pH = 6.0 
E) pH = 3.0 
A) pH = 12.5 
B) pH = 11 
C) pH = 8.3 
D) pH = 6.0 
E) pH = 3.0

Question 4

An aqueous solution contains 0.050 M of methylamine. The concentration of H+ in this solution is ________ M. Kb for methylamine is 4.4 × 10-4.

Accepted Answer

A) 0.050 
B) 2.2 × 10-13 
C) 2.9 × 10-13 
D) 4.5 × 10-13 
E) 2.2 × 10-12 
A) 0.050 
B) 2.2 × 10-13 
C) 2.9 × 10-13 
D) 4.5 × 10-13 
E) 2.2 × 10-12

Question 5

The conjugate base of HSO4- is ________.

Accepted Answer

A) OH- 
B) H2SO4 
C) SO42- 
D) HSO4+ 
E) H3SO4+ 
A) OH- 
B) H2SO4 
C) SO42- 
D) HSO4+ 
E) H3SO4+

Question 6

Of the following, which is the strongest acid?

Accepted Answer

A) HIO4 
B) HIO3 
C) HIO2 
D) HIO 
E) The acid strength of all of the above is the same. 
A) HIO4 
B) HIO3 
C) HIO2 
D) HIO 
E) The acid strength of all of the above is the same.

Question 7

The pH of a 0.55 M aqueous solution ammonia, NH3, at 25.0 °C is 11.50. What is the value of Kb for NH3?

Accepted Answer

A) 2.0 × 10-9 
B) 1.1 × 10-9 
C) 6.0 × 10-5 
D) 1.8 × 10-5 
E) none of the above 
A) 2.0 × 10-9 
B) 1.1 × 10-9 
C) 6.0 × 10-5 
D) 1.8 × 10-5 
E) none of the above

Question 8

Of the following, which is the strongest acid?

Accepted Answer

A) HClO 
B) HClO3 
C) HClO2 
D) HClO4 
E) HIO 
A) HClO 
B) HClO3 
C) HClO2 
D) HClO4 
E) HIO

Question 9

Kb for NH3 is 1.8 × 10-5. What is the pOH of a 0.20 M aqueous solution of NH4Cl at 25.0 °C?

Accepted Answer

A) 2.72 
B) 11.28 
C) 9.02 
D) 4.98 
E) 11.23 
A) 2.72 
B) 11.28 
C) 9.02 
D) 4.98 
E) 11.23

Question 10

An aqueous solution contains 0.10 M HNO3. The solution is ________.

Accepted Answer

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

Question 11

Calculate the pH of a solution at 25.0 °C that contains 1.94 × 10-10 M hydronium ions.

Accepted Answer

A) 1.94 
B) 4.29 
C) 7.00 
D) 14.0 
E) 9.71 
A) 1.94 
B) 4.29 
C) 7.00 
D) 14.0 
E) 9.71

Question 12

The base-dissociation constant, Kb, for pyridine, C5H5N, is 1.4 × 10-9. The acid-dissociation constant, Ka, for the pyridinium ion, C5H5NH+, is ________.

Accepted Answer

A) 1.0 × 10-7 
B) 1.4 × 10-23 
C) 7.1 × 10-4 
D) 1.4 × 10-5 
E) 7.1 × 10-6 
A) 1.0 × 10-7 
B) 1.4 × 10-23 
C) 7.1 × 10-4 
D) 1.4 × 10-5 
E) 7.1 × 10-6

Question 13

The Ka of hypochlorous acid (HClO)is 3.0 × 10-8 at 25 °C. What is the percent ionization of hypochlorous acid in a 0.015 M aqueous solution of HClO at 25 °C?

Accepted Answer

A) 4.5 × 10-8 
B) 14 
C) 2.1 × 10-5 
D) 0.14 
E) 1.4 × 10-3 
A) 4.5 × 10-8 
B) 14 
C) 2.1 × 10-5 
D) 0.14 
E) 1.4 × 10-3

Question 14

The pH of an aqueous solution at 25.0 °C is 10.55. What is the molarity of H+ in this solution?

Accepted Answer

A) 2.8 × 10-11 
B) 3.5 × 10-4 
C) 3.45 
D) 1.1 × 10-13 
E) 3.5 × 1010 
A) 2.8 × 10-11 
B) 3.5 × 10-4 
C) 3.45 
D) 1.1 × 10-13 
E) 3.5 × 1010

Question 15

Calculate the concentration (in M)of hydroxide ions in a solution at 25.0 °C with a pOH of 4.223.

Accepted Answer

A) 5.98 × 10-5 
B) 1.67 × 10-10 
C) 1.67 × 104 
D) 5.99 × 10-19 
E) 1.00 × 10-7 
A) 5.98 × 10-5 
B) 1.67 × 10-10 
C) 1.67 × 104 
D) 5.99 × 10-19 
E) 1.00 × 10-7

Question 16

Using the data in the table, which of the conjugate acids below is the weakest acid?

Accepted Answer

A) HClO 
B) HCO3- 
C) H2S 
D) NH3CH3+ 
E) H2S and HClO 
A) HClO 
B) HCO3- 
C) H2S 
D) NH3CH3+ 
E) H2S and HClO

Question 17

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

Question 18

What is the conjugate acid of NH3?

Accepted Answer

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

Question 19

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) 2.96 
C) 11.07 
D) 13.24 
E) 7.00 
A) 0.74 
B) 2.96 
C) 11.07 
D) 13.24 
E) 7.00

Question 20

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

Accepted Answer

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

Exam 16: Acid-Base Equilibria

The acid-dissociation constant of hydrocyanic acid (HCN)at 25.0 °C is 4.9 × 10-10. What is the pH of an aqueous solution of 0.050 M sodium cyanide (NaCN)?

Of the following substances, an aqueous solution of ________ will form basic solutions. NH4Cl Cu(NO3)2 K2CO3 NaF

Which solution below has the highest concentration of hydroxide ions?

An aqueous solution contains 0.050 M of methylamine. The concentration of H+ in this solution is ________ M. Kb for methylamine is 4.4 × 10-4.

The conjugate base of HSO4- is ________.

Of the following, which is the strongest acid?

The pH of a 0.55 M aqueous solution ammonia, NH3, at 25.0 °C is 11.50. What is the value of Kb for NH3?

Of the following, which is the strongest acid?

Kb for NH3 is 1.8 × 10-5. What is the pOH of a 0.20 M aqueous solution of NH4Cl at 25.0 °C?

An aqueous solution contains 0.10 M HNO3. The solution is ________.

Calculate the pH of a solution at 25.0 °C that contains 1.94 × 10-10 M hydronium ions.

The base-dissociation constant, Kb, for pyridine, C5H5N, is 1.4 × 10-9. The acid-dissociation constant, Ka, for the pyridinium ion, C5H5NH+, is ________.

The Ka of hypochlorous acid (HClO)is 3.0 × 10-8 at 25 °C. What is the percent ionization of hypochlorous acid in a 0.015 M aqueous solution of HClO at 25 °C?

The pH of an aqueous solution at 25.0 °C is 10.55. What is the molarity of H+ in this solution?

Calculate the concentration (in M)of hydroxide ions in a solution at 25.0 °C with a pOH of 4.223.

Using the data in the table, which of the conjugate acids below is the weakest acid?

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 ________.

What is the conjugate acid of NH3?

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

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

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The acid-dissociation constant of hydrocyanic acid (HCN)at 25.0 °C is 4.9 × 10^-¹⁰. What is the pH of an aqueous solution of 0.050 M sodium cyanide (NaCN)?

Of the following substances, an aqueous solution of ________ will form basic solutions. NH₄Cl Cu(NO₃)₂ K₂CO₃ NaF

An aqueous solution contains 0.050 M of methylamine. The concentration of H⁺ in this solution is ________ M. K_b for methylamine is 4.4 × 10^-4.

The conjugate base of HSO₄^- is ________.

The pH of a 0.55 M aqueous solution ammonia, NH₃, at 25.0 °C is 11.50. What is the value of K_b for NH₃?

K_b for NH₃ is 1.8 × 10^-⁵. What is the pOH of a 0.20 M aqueous solution of NH₄Cl at 25.0 °C?

An aqueous solution contains 0.10 M HNO₃. The solution is ________.

Calculate the pH of a solution at 25.0 °C that contains 1.94 × 10^-10 M hydronium ions.

The base-dissociation constant, K_b, for pyridine, C₅H₅N, is 1.4 × 10^-9. The acid-dissociation constant, K_a, for the pyridinium ion, C₅H₅NH⁺, is ________.

The K_a of hypochlorous acid (HClO)is 3.0 × 10^-8 at 25 °C. What is the percent ionization of hypochlorous acid in a 0.015 M aqueous solution of HClO at 25 °C?

The pH of an aqueous solution at 25.0 °C is 10.55. What is the molarity of H⁺ in this solution?

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_a of HZ is ________.

What is the conjugate acid of NH₃?

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