Question 1

Which of the following is the correct definition of Lewis acids and bases?

Accepted Answer

A) A Lewis acid is an electron acceptor while a Lewis base is an electron donor. 
B) A Lewis acid is an electron pair donor while a Lewis base is an electron pair acceptor. 
C) A Lewis acid is an electron donor while a Lewis base is an electron acceptor. 
D) A Lewis acid is an electron pair acceptor while a Lewis base is a proton donor. 
E) A Lewis acid is an electron pair acceptor while a Lewis base is an electron pair donor. 
A) A Lewis acid is an electron acceptor while a Lewis base is an electron donor. 
B) A Lewis acid is an electron pair donor while a Lewis base is an electron pair acceptor. 
C) A Lewis acid is an electron donor while a Lewis base is an electron acceptor. 
D) A Lewis acid is an electron pair acceptor while a Lewis base is a proton donor. 
E) A Lewis acid is an electron pair acceptor while a Lewis base is an electron pair donor.

Question 2

Which one of the following salts, when dissolved in water, produces the solution with a pH closest to 7.00?

Accepted Answer

A) NH4ClO4 
B) NaO 
C) NaCO3 
D) KI 
A) NH4ClO4 
B) NaO 
C) NaCO3 
D) KI

Question 3

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) 3.3 
D) 1.1 × 10-13 
E) 3.5 × 1010 
A) 2.8 × 10-11 
B) 3.5 × 10-4 
C) 3.3 
D) 1.1 × 10-13 
E) 3.5 × 1010

Question 4

Calculate the pH of a 1.60 mol L-1 CH3NH3Cl solution. Kb for methylamine, CH3NH2, is 3.7 × 10-4.

Accepted Answer

A) 1.61 
B) 5.18 
C) 8.82 
D) 12.39 
A) 1.61 
B) 5.18 
C) 8.82 
D) 12.39

Question 5

Which of the following is a conjugate acid-base pair?

Accepted Answer

A) NH4+/NH3 
B) H3O⁺/OH⁻ 
C) H2SO3/SO32⁻ 
D) SO42-/SO32- 
E) NaOH/Na+ 
A) NH4+/NH3 
B) H3O⁺/OH⁻ 
C) H2SO3/SO32⁻ 
D) SO42-/SO32- 
E) NaOH/Na+

Question 6

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 0.080 mol L-1 sodium cyanide (NaCN)?

Accepted Answer

A) 11.11 
B) 2.89 
C) 1.3 × 10-3 
D) 7.8 × 10-12 
E) 3.9 × 10-11 
A) 11.11 
B) 2.89 
C) 1.3 × 10-3 
D) 7.8 × 10-12 
E) 3.9 × 10-11

Question 7

Calculate the pOH of a solution that contains 3.9 × 10-4 mol L-1 H3O⁺ at 25 °C.

Accepted Answer

A) 4.59 
B) 3.31 
C) 10.59 
D) 9.14 
E) 0.59 
A) 4.59 
B) 3.31 
C) 10.59 
D) 9.14 
E) 0.59

Question 8

Determine the pH of a 0.22 mol L-1 NaF solution at 25 °C. The Ka of HF is 3.5 × 10-5.

Accepted Answer

A) 10.20 
B) 5.10 
C) 8.90 
D) 11.44 
E) 2.56 
A) 10.20 
B) 5.10 
C) 8.90 
D) 11.44 
E) 2.56

Question 9

What is the difference between a strong and weak acid?

Accepted Answer

A strong acid ionizes/dissocia

Question 10

Which of the following increases the strength of an oxo acid, HYOn?

Accepted Answer

A) increasing the electron affinity of Y and increasing the number of oxygen atoms, n 
B) decreasing the electron affinity of Y and increasing the number of oxygen atoms, n 
C) increasing the electron affinity of Y and decreasing the number of oxygen atoms, n 
D) decreasing the electron affinity of Y and decreasing the number of oxygen atoms, n 
E) lowering the electron affinity of Y and increasing the number of oxygen atoms, n 
A) increasing the electron affinity of Y and increasing the number of oxygen atoms, n 
B) decreasing the electron affinity of Y and increasing the number of oxygen atoms, n 
C) increasing the electron affinity of Y and decreasing the number of oxygen atoms, n 
D) decreasing the electron affinity of Y and decreasing the number of oxygen atoms, n 
E) lowering the electron affinity of Y and increasing the number of oxygen atoms, n

Question 11

Identify the triprotic acid.

Accepted Answer

A) HNO3 
B) H3PO4 
C) H2SO3 
D) HClO4 
E) H2SO4 
A) HNO3 
B) H3PO4 
C) H2SO3 
D) HClO4 
E) H2SO4

Question 12

The base-dissociation constant of ethylamine (C2H5NH2)is 6.4 × 10-4 at 25.0 °C. The [H+] in a 1.6 × 10-2 mol L-1 solution of ethylamine is ________ mol L-1.

Accepted Answer

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

Question 13

Which of the following acids is the strongest? The acid is followed by its Ka value.

Accepted Answer

A) HF, 3.5 × 10-4 
B) HCN, 4.9 × 10-10 
C) HNO2, 4.6 × 10-4 
D) HCHO2, 1.8 × 10-4 
E) HClO2, 1.1 × 10-2 
A) HF, 3.5 × 10-4 
B) HCN, 4.9 × 10-10 
C) HNO2, 4.6 × 10-4 
D) HCHO2, 1.8 × 10-4 
E) HClO2, 1.1 × 10-2

Question 14

Order the following acids in order of increasing strength: HBrO HBrO3 HBrO4 HBrO2

Accepted Answer

A) HBrO 3 HBrO4 2 
B) HBrO4 3 HBrO2 3 HBrO2 4 
D) HBrO 2 HBrO3 4 
E) HBrO2 4 HBrO 2 
A) HBrO 3 HBrO4 2 
B) HBrO4 3 HBrO2 3 HBrO2 4 
D) HBrO 2 HBrO3 4 
E) HBrO2 4 HBrO 2

Question 15

Determine the pH of a 0.62 mol L-1 NH4NO3 solution at 25 °C. The Kb for NH3 is 1.76 × 10-5.

Accepted Answer

A) 2.48 
B) 9.27 
C) 11.52 
D) 4.73 
E) 9.45 
A) 2.48 
B) 9.27 
C) 11.52 
D) 4.73 
E) 9.45

Question 16

Calculate the concentration of bicarbonate ion, HCO3-, in a 0.010 mol L-1 H2CO3 solution that has the stepwise dissociation constants Ka1 = 4.3 × 10-7 and Ka2 = 5.6 × 10-11.

Accepted Answer

A) 6.6 × 10-5 mol L-1 
B) 4.3 × 10-7 mol L-1 
C) 4.3 × 10-9 mol L-1 
D) 5.6 × 10-11 mol L-1 
A) 6.6 × 10-5 mol L-1 
B) 4.3 × 10-7 mol L-1 
C) 4.3 × 10-9 mol L-1 
D) 5.6 × 10-11 mol L-1

Question 17

Which of the following is an acid-base neutral ion?

Accepted Answer

A) Al3+ 
B) CN- 
C) CO32- 
D) Cl- 
E) NH4+ 
A) Al3+ 
B) CN- 
C) CO32- 
D) Cl- 
E) NH4+

Question 18

Calculate the concentration of OH⁻ in a solution that contains 3.9 × 10-4 mol L-1 H3O⁺ at 25 °C. Also identify the solution as acidic, basic, or neutral.

Accepted Answer

A) 2.6 × 10-11 mol L-1, acidic 
B) 2.6 × 10-11 mol L-1, basic 
C) 3.9 × 10-4 mol L-1, neutral 
D) 2.7 × 10-2 mol L-1, basic 
E) 2.7 × 10-2 mol L-1, acidic 
A) 2.6 × 10-11 mol L-1, acidic 
B) 2.6 × 10-11 mol L-1, basic 
C) 3.9 × 10-4 mol L-1, neutral 
D) 2.7 × 10-2 mol L-1, basic 
E) 2.7 × 10-2 mol L-1, acidic

Question 19

Which of the following species is amphoteric?

Accepted Answer

A) CO32- 
B) HCl 
C) NH4⁺ 
D) HPO42- 
E) NaOH 
A) CO32- 
B) HCl 
C) NH4⁺ 
D) HPO42- 
E) NaOH

Question 20

Calculate the pH for an aqueous solution of pyridine that contains 2.15 × 10-4 mol L-1 hydroxide ion.

Accepted Answer

A) 4.65 × 10-11 
B) 2.15 × 10-4  
C) 3.67 
D) 10.33 
A) 4.65 × 10-11 
B) 2.15 × 10-4  
C) 3.67 
D) 10.33

Exam 15: Acids and Bases

Which of the following is the correct definition of Lewis acids and bases?

Which one of the following salts, when dissolved in water, produces the solution with a pH closest to 7.00?

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

Calculate the pH of a 1.60 mol L-1 CH3NH3Cl solution. Kb for methylamine, CH3NH2, is 3.7 × 10-4.

Which of the following is a conjugate acid-base pair?

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 0.080 mol L-1 sodium cyanide (NaCN)?

Calculate the pOH of a solution that contains 3.9 × 10-4 mol L-1 H3O⁺ at 25 °C.

Determine the pH of a 0.22 mol L-1 NaF solution at 25 °C. The Ka of HF is 3.5 × 10-5.

What is the difference between a strong and weak acid?

Which of the following increases the strength of an oxo acid, HYOn?

Identify the triprotic acid.

The base-dissociation constant of ethylamine (C2H5NH2)is 6.4 × 10-4 at 25.0 °C. The [H+] in a 1.6 × 10-2 mol L-1 solution of ethylamine is ________ mol L-1.

Which of the following acids is the strongest? The acid is followed by its Ka value.

Order the following acids in order of increasing strength: HBrO HBrO3 HBrO4 HBrO2

Determine the pH of a 0.62 mol L-1 NH4NO3 solution at 25 °C. The Kb for NH3 is 1.76 × 10-5.

Calculate the concentration of bicarbonate ion, HCO3-, in a 0.010 mol L-1 H2CO3 solution that has the stepwise dissociation constants Ka1 = 4.3 × 10-7 and Ka2 = 5.6 × 10-11.

Which of the following is an acid-base neutral ion?

Calculate the concentration of OH⁻ in a solution that contains 3.9 × 10-4 mol L-1 H3O⁺ at 25 °C. Also identify the solution as acidic, basic, or neutral.

Which of the following species is amphoteric?

Calculate the pH for an aqueous solution of pyridine that contains 2.15 × 10-4 mol L-1 hydroxide ion.

Units of Measurement for Physical and Chemical Change

Atoms and Elements

Molecules, Compounds, and Nomenclature

Chemical Reactions and Stoichiometry

Gases

Thermochemistry

The Quantum-Mechanical Model of the Atom

Periodic Properties of the Elements

Chemical Bonding I: Lewis Theory

Chemical Bonding Ii: Molecular Shapes, Valence Bond Theory, and Molecular Orbital Theory

Liquids, Solids, and Intermolecular Forces

Solutions

Chemical Kinetics

Chemical Equilibrium

Aqueous Ionic Equilibrium

Gibbs Energy and Thermodynamics

Electrochemistry

Radioactivity and Nuclear Chemistry

Organic Chemistry I: Structures

Organic Chemistry II: Reactions

Biochemistry

Chemistry of the Nonmetals

Metals and Metallury

Transition Metals and Coordination Compounds

Filters

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

Calculate the pH of a 1.60 mol L^-1 CH₃NH₃Cl solution. K_b for methylamine, CH₃NH₂, is 3.7 × 10^-4.

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 0.080 mol L^-1 sodium cyanide (NaCN)?

Calculate the pOH of a solution that contains 3.9 × 10^-4 mol L^-1 H₃O⁺ at 25 °C.

Determine the pH of a 0.22 mol L^-1 NaF solution at 25 °C. The K_a of HF is 3.5 × 10^-5.

Which of the following increases the strength of an oxo acid, HYO_n?

The base-dissociation constant of ethylamine (C₂H₅NH₂)is 6.4 × 10^-4 at 25.0 °C. The [H⁺] in a 1.6 × 10^-2 mol L^-1 solution of ethylamine is ________ mol L^-1.

Which of the following acids is the strongest? The acid is followed by its K_a value.

Order the following acids in order of increasing strength: HBrO HBrO3 ^HBrO4HBrO₂

Determine the pH of a 0.62 mol L^-1 NH₄NO₃ solution at 25 °C. The K_b for NH₃ is 1.76 × 10^-5.

Calculate the concentration of bicarbonate ion, HCO₃^-, in a 0.010 mol L^-1 H₂CO₃ solution that has the stepwise dissociation constants K_a1 = 4.3 × 10^-7 and K_a2 = 5.6 × 10^-11.

Calculate the concentration of OH⁻ in a solution that contains 3.9 × 10^-4 mol L^-1 H₃O⁺ at 25 °C. Also identify the solution as acidic, basic, or neutral.

Calculate the pH for an aqueous solution of pyridine that contains 2.15 × 10^-4 mol L^-1 hydroxide ion.