Chemistry Chapter 5 A net ionic equation is obtained when the ions forming

General Chemistry, 11e (Petrucci)

Chapter 5 Introduction to Reactions in Aqueous Solutions

1) Soluble ionic compounds form strong electrolytes.

2) The hydrated proton attracts only one water molecule.

3) An insoluble compound will dissolve to an appreciable amount in water.

4) A solid forming from a mixture of solutions is called a precipitate.

5) Weak acids almost completely dissociate.

6) In 0.20 M NH3(aq), the concentration of NH4+(aq) and OH–(aq) are approximately 0.20 M.

7) Oxidation never occurs alone.

8) For redox reactions to be balanced, electrons should be present on the reactant side.

9) An oxidizing agent is reduced during a redox reaction.

10) A reducing agent causes itself to be reduced.

11) A titration is a method of adding small amounts of one reactant until the reaction is complete.

12) Choose the INCORRECT statement.

A) A non-electrolyte does not form ions in aqueous solution and does not conduct an electric current.

B) A strong electrolyte is completely ionized in aqueous solution.

C) A strong electrolyte in aqueous solution is a good electrical conductor.

D) A weak electrolyte in aqueous solution is a good electrical conductor.

E) A weak electrolyte is partially ionized in a aqueous solution.

13) Most water-soluble compounds of Group 1A or 2A elements are:

A) strong electrolytes

B) strong acids

C) weak electrolytes

D) weak acids

E) nonelectrolytes

14) Which of the following solutions has the highest fluoride concentration?

A) 0.05 M CaF2

B) 2.1 mg/L NaF

C) a solution having 1.5 mg/L F–

D) a solution having 0.06 M F–

E) 0.05 M NaF

15) Which of the following aqueous solutions is probably the poorest electrical conductor?

A) 0.5 M K2SO4

B) 0.5 M CaCl2

C) 0.5 M HF

D) 0.5 M CH3OH

E) 0.5 M NH3

3

16) Which of the following aqueous solutions has the lowest concentration of sulfate ion?

A) 0.1 M Al2(SO4)3

B) 0.2 M MgSO4

C) 0.3 M Li2SO4

D) 0.4 M K2SO4

E) 0.5 M CuSO4

17) What concentration of Fe2(SO4)3(aq) is required for the solution to have [Fe3+(aq)] = 0.32 M?

A) 0.16 M

B) 0.32 M

C) 0.64 M

D) 0.080 M

E) 0.12 M

18) What is the concentration of Br–(aq) in a solution prepared by mixing 75.0 mL of 0.62 M iron(III)

bromide with 75.0 mL of water? Assume that the volumes of the solutions are additive.

A) 0.93 M

B) 0.31 M

C) 1.9 M

D) 0.62 M

E) 1.23 M

19) To precipitate Cd2+(aq) from solution one could add:

A) H2S(aq)

B) HCl(aq)

C) HNO3(aq)

D) KI(aq)

E) NaCl(aq)

20) Which statement below best describes net ionic equations?

A) A net ionic equation lists all ions in the solution.

B) A net ionic equation is obtained when the ions forming the precipitate are removed from the molecular

equation.

C) A net ionic equation is a balanced chemical equation that includes only ions that participate in a

reaction.

D) A net ionic equation is a balanced chemical equation that includes all the ions present in a reaction

mixture.

E) A net ionic reaction is a balanced chemical equation that clearly shows spectator ions in a reaction.

21) To precipitate Ba2+(aq) from solution, one could add:

A) HCl(aq)

B) (NH4)2CO3(aq) in NH3(aq)

C) H2S(aq) in NH3/NH4+(aq)

D) H2S(aq) in 0.3 M HCl(aq)

E) NaCl(aq)

22) Which of the following pairs of aqueous solutions will give a precipitate when mixed?

A) K3PO4 and CaCl2

B) LiClO4 and Ba(OH)2

C) AgNO3 and Ca(ClO4)2

D) NaCl and K(CH3COO)

E) Sr(NO3)2 and KI

23) Choose the INCORRECT statement.

A) Most molecular compounds are either nonelectrolytes or weak electrolytes.

B) Most ionic compounds are strong electrolytes.

C) A precipitate is formed when certain anions and cations react to form an insoluble ionic solid.

D) Net ionic equations include only the actual participants of the reaction.

E) An acid produces hydride ions in solution.

24) Which of the following, in aqueous solution, is most likely to behave as a weak acid?

A) HCl

B) HCN

C) NaCl

D) NaCN

E) NH3

25) The substance HI is a:

A) strong acid

B) weak base

C) strong base

D) salt

E) weak acid

26) The substance KOH is a:

A) weak acid

B) salt

C) weak base

D) strong base

E) strong acid

27) The substance HNO2 is a:

A) strong base

B) strong acid

C) weak acid

D) weak base

E) salt

28) The substance BaCl2 is a:

A) salt

B) weak acid

C) strong base

D) weak base

E) strong acid

29) The substance NH3 is a:

A) weak acid

B) strong acid

C) salt

D) weak base

E) strong base

30) The substance NaOH in water solution is a:

A) nonelectrolyte

B) weak electrolyte

C) weak base

D) strong electrolyte

E) weak acid

31) The substance CH3COOH in water is a:

A) strong electrolyte

B) weak electrolyte

C) nonelectrolyte

D) strong acid

E) strong base

32) The substance C5H5OH in water solution is a:

A) weak electrolyte

B) strong acid

C) strong electrolyte

D) nonelectrolyte

E) strong base

33) The substance KClO4 in water solution is a:

A) strong electrolyte

B) nonelectrolyte

C) weak electrolyte

D) strong base

E) weak acid

34) Which of the following would have the strongest tendency for producing H+ ions in an aqueous

solution?

A) NH3

B) HNO2

C) H2S

D) HNO3

E) CH3COOH

35) Which of the following would have the strongest tendency of producing OH– ions in an aqueous

solution?

A) Fe(OH)2

B) Fe(OH)3

C) Ba(OH)2

D) NaOH

E) HOCl

36) Choose the INCORRECT statement.

A) A base produces hydrogen ions in solution.

B) A strong acid is a strong electrolyte.

C) Weak acids are weak electrolytes.

D) In a neutralization reaction, an acid reacts with a base.

E) Acids contain ionizable hydrogens.

37) Which of the following represents a neutralization reaction?

A) 2 H2(g) + O2(g) → 2 H2O(l)

B) NH3(aq) + HCl(aq) → NH4Cl(aq)

C) 2 NaOH(aq) + CuCl2(aq) → 2 NaCl(aq) + Cu(OH)2(s)

D) HBr(aq) + AgNO3(aq) → HNO3(aq) + AgBr(s)

E) 2 H2O2(aq) → 2 H2O(l) + O2(g)

38) Assuming that the proposed aqueous reactants are mixed in stoichiometric ratios, and at moderate

concentrations, which of the following is least likely to represent an observable (e.g., gas evolution or

precipitation) reaction?

A) Ca2+ + 2 Cl– + 2 K+ + CO32- → ?

B) 2 Na+ + CO32- + 2 HC2N3O2 → ?

C) H2S + Cu2+ + SO42- → ?

D) H2SO3 + Li+ + Cl– → ?

E) Pb2+ + 2 NO3– + 2 Na+ + 2 OH– → ?

39) Which of the following compounds is quite insoluble in water, but would liberate a gas when treated

with aqueous acetic acid?

A) K2CO3

B) K2SO4

C) CaCO3

D) CaSO4

E) AgCl

40) Which of the following combinations is correct?

A) NaOH/weak base

B) H3PO4/strong acid

C) HNO3/weak acid

D) NH3/strong base

E) HClO4/strong acid

41) Which of the following pairs react to give both a precipitation and a neutralization reaction?

A) Ca(OH)2(aq) and H2SO4(aq)

B) Mg(OH)2(aq) and H2SO4(aq)

C) Sr(OH)2(aq) and HNO3(aq)

D) Ba(OH)2(aq) and HNO3(aq)

42) Select a statement that best describes the oxidation process.

A) In the oxidation process all elements change oxidation state.

B) In the oxidation process all elements experience an increase in oxidation state.

C) In the oxidation process some elements change their oxidation state.

D) In the oxidation process some elements experience oxidation state increase.

E) In the oxidation process only oxygen increases its oxidation state.

43) In which of the following pairs is the oxidation number for the underlined element INCORRECT?

A) MnO4–/(+7 )

B) SO42-/(+4)

C) NH4+/(-3)

D) NO3–/(+5)

E) Cr2O72-/(+6)

44) In which of the following pairs is the oxidation number for the underlined element INCORRECT?

A) MnO2/(+4 )

B) SO32-/(+4)

C) ClO3–/(+7)

D) NO2–/(+3)

E) Cr2O3/(+3)

45) In which of the following pairs is the oxidation number for the underlined element INCORRECT?

A) ClO4–/(+7)

B) S2O32-/(+2)

C) Fe2O3/(+3)

D) HCO3–/(+3)

E) CO2/(+4)

46) Among the following reactions, find those that are redox reactions:

1) MnO4–(aq) + 5 Fe2+(aq) + 8 H+(aq) → 5 Fe3+(aq) + Mn2+(aq) + 4 H2O(l)

2) 6 HF(aq) + Al(OH)3(s) + 3 NaOH(aq) → Na3AlF6(s) + 6 H2O(l)

3) Au(s) + 4 H+ (aq)+ NO3–(aq)+ 4 Cl–(aq)→ [AuCl4]– (aq)+ 2 H2O + NO(g)

4) FeS(s) + 2 HCl(aq) → FeCl2(aq) + H2S(g)

5) SiO2(s) + 4HF(aq) → SiF4(g) + H2O(l)

A) reaction 1)

B) reaction 2)

C) reactions 1) and 3)

D) reactions 2) and 5)

E) reaction 4)

47) Among the following reactions, find those that are redox reactions:

1) HOCl(aq) + NaOH(aq) → NaOCl(aq) + H2O(l)

2) 5 I–(aq) + IO3–(aq) + 6 H+(aq) → 3 I2(s) + 3 H2O(l)

3) 2NaCl(s) + H2SO4(aq) →2 HCl(g) + Na2SO4(s)

4) CaO(s) + H2O(l)→ Ca(OH)2(aq)

5) 2 H2O2(aq) → 2 H2O(l) + O2(g)

A) reactions 1) and 3)

B) reactions 1) and 5)

C) reactions 2) and 4)

D) reactions 2) and 5)

E) reactions 3) and 4)

48) Which of the following reactions is an oxidation-reduction reaction?

A) NH4HS(s) → NH3(g) + H2S(g)

B) 2 NaHCO3(s) → Na2CO3(s) + H2O(g) + CO2(g)

C) N2O4(g) → 2 NO2(g)

D) 2 SO2(g) + O2(g) → 2 SO3(g)

E) 2 CH3COOH(aq) + Ba(OH)2(aq) → Ba(CH3COO)2(aq) + 2 H2O(l)

49) In which of the following pairs is the oxidation number for the underlined element INCORRECT?

A) BrO4–/(+7)

B) CO32-/(+4)

C) FeO/ (+2)

D) IO3–/(+5 )

E) Mg(OH)2/(+3 )

50) Which of the following reactions is an oxidation-reduction reaction?

A) NH3(g) + H2O(l) → NH4OH(aq)

B) HCl(aq) + NaH2PO4(aq) → H3PO4(aq) + NaCl(aq)

C) 2 H2O(l) → H3O+(aq) + OH–(aq)

D) Mg(OH)2(s) → Mg2+(aq) + 2 OH–(aq)

E) CO(g) + H2O(g) → CO2(g) + H2(g)

51) A disproportionation reaction is one in which:

A) the equation is not balanced

B) the same substance is oxidized and reduced

C) more of one substance reacts than another

D) water must be added

E) both reactants are reduced

52) Which of the following represents a disproportionation reaction?

A) Br2(l) + H2O(l) → HOBr(aq) + Br–(aq) + H+(aq)

B) S(s) + SO2(g) + H2O(l) → S2O32-(aq) + 2 H+(aq)

C) HOCl(aq) + OH–(aq) → H2O(l) + OCl–(aq)

D) 3 S2-(aq) + 2 CrO42-(aq) + 8 H2O(l) → 3 S(s) + 2 Cr(OH)3(s) + 10 OH–(aq)

E) HF(aq) → H+(aq) + F–(aq)

53) Which of the following is most likely to act as a reducing agent?

A) H2S

B) H2SO5

C) SO3

D) H2SO4

E) H2S2O8

54) Which of the following is most likely to be a strong oxidizing agent?

A) MnO

B) MnO2

C) KMnO4

D) Mn2O3

E) Mn3O4

55) Trace amounts of oxygen gas can be “scrubbed” from gases using the following reaction:

4 Cr2+(aq) + O2(g) + 4 H+(aq) → 4 Cr3+(aq) + 2 H2O(l)

Which of the following statements is true regarding this reaction?

A) Oxygen gas is reduced to water.

B) Cr2+(aq) is the oxidizing agent.

C) O2(g) is the reducing agent.

D) Electrons are transferred from O2 to Cr2+.

56) 12.5 mL of 0.280 M HNO3(aq) and 5.0 mL of 0.920 M KOH(aq) are mixed. Is the resulting solution

acidic, basic, or neutral?

A) acidic

B) basic

C) neutral

D) HNO3 and KOH don’t mix.

57) Iron in the form FeCl2 can be determined by titration with potassium dichromate:

6 FeCl2(aq) + K2Cr2O7(aq) + 14 HCl(aq) → 6 FeCl3(aq) + 2 CrCl3(aq) + 2 KCl(aq) + 7 H2O(l)

An iron sample of mass 0.800 g required 18.80 mL of 0.0120 M K2Cr2O7(aq) to reach the end point. How

many moles of FeCl2 were in the sample?

A) 1.43 × 10-2 mol

B) 1.35 × 10–3 mol

C) 3.75 × 10–5 mol

D) 2.26 × 10–4 mol

E) 1.13 × 10–4 mol

58) A solution is 0.660 M in HNO3(aq) and 1.02 M in Ca(NO3)2(aq). What is the molarity of NO3–(aq) in

the solution?

A) 2.70 M

B) 1.68 M

C) 1.02 M

D) 0.660 M

E) 0.360 M

59) Write the net ionic equation for the reaction of aqueous solutions of barium chloride and sodium

sulfate.

A) BaCl(aq) + NaSO4(aq) → BaSO4(s) + NaCl(aq)

B) BaCl(aq) + SO42- (aq)→ BaSO4(s) + Ba2+ (aq)

C) Ba2+(aq) + SO42-(aq) → BaSO4(aq)

D) Ba2+ (aq)+ SO42- (aq)→ BaSO4(s)

E) no reaction

60) Write the net ionic equation for the reaction of lead(II) nitrate and sodium iodide.

A) Pb(NO3)2(aq) + 2 NaI(aq) → PbI2(s) + 2 NaNO3(aq)

B) Pb2+(aq)+ 2 NaI(aq) → PbI2(s) + 2 Na

C) Pb2+(aq)+ 2 I–(aq)→ PbI2(s)

D) Pb2+(aq)+ 2 I–(aq)→ Pb2+(aq)+ 2 I-(aq)

E) no reaction

61) Indicate whether a precipitate forms by completing equation

Li+(aq) + Br–(aq) + Pb2+(aq) + NO3–(aq) → ?

A) PbBr2(s) + LiNO3(s)

B) Pb2+(aq) + 2 Br–(aq) + LiNO3(s)

C) Pb(NO3)2(s) + Li+(aq) + 2 Br–(aq)

D) PbBr2(s) + Li+(aq) + NO3–(aq)

E) no reaction

62) Indicate whether a precipitate forms by completing equation

Ag+(aq) + Br–(aq) + NO3–(aq) + K+(aq) → ?

A) AgBr(s) + K+(aq) + NO3–(aq)

B) AgNO3(s) + K+(aq) + Br–(aq)

C) AgBr(s) + KNO3(s)

D) KNO3(s) + Ag+(aq) + Br–(aq)

E) no reaction

63) Indicate whether a precipitate forms by completing equation

Na+(aq) + Cl–(aq) + NO3–(aq) + K+(aq) → ?

A) NaCl(s) + NO3–(aq) + K+(aq)

B) NaNO3(s) + K+(aq) + Cl–(aq)

C) KCl(s) + Na+(aq) + NO3–(aq)

D) KNO3(s) + Na+(aq) + Cl–(aq)

E) no reaction

64) Complete the equation and indicate if a precipitate forms.

Na+(aq) + OH–(aq) + Mg2+(aq) + Cl–(aq) →

A) NaCl(s) + Mg2+(aq) + 2 OH–(aq)

B) Mg(OH)2(s) + Na+(aq) + Cl–(aq)

C) MgCl2(s) + Na+(aq) + OH–(aq)

D) MgCl2(s) + NaOH(s)

E) no reaction

65) Write the net ionic equation for the reaction of magnesium carbonate and nitric acid.

A) MgCO3(s) + 2 H+(aq) → Mg2+(aq) + H2O(l) + CO2(g)

B) MgCO3(s) + 2 HNO3(aq) → Mg(NO3)2(aq) + H2O(l) + CO2(g)

C) MgCO3(s) + 2 HNO3(aq) → Mg(NO3)2(aq) + H2CO3(aq)

D) Mg2+(aq) + CO32-(aq) + 2 H+(aq) → Mg2+(aq) + H2O(l) + CO2(g)

E) no reaction

66) Write the net ionic equation for the reaction of ammonium chloride and potassium hydroxide.

A) NH4Cl(aq) + KOH(aq) → NH3(aq) + KCl(aq) + H2O(l)

B) NH4+(aq) + OH–(aq) → NH3(aq) + H2O(l)

C) NH4Cl(aq) + OH–(aq) → NH3(aq) + Cl–(aq) + H2O(l)

D) NH4+(aq) + KOH(s) → NH4OH(aq) + K+(aq)

E) no reaction

67) Write the net ionic equation for the reaction of ammonium chloride and iron(III) hydroxide.

A) 3 NH4Cl(aq) + Fe(OH)3(s) → 3 NH3(aq) + 3 H2O(l) + FeCl3(s)

B) 3 NH4+(aq) + 3 OH–(aq) → 3 NH3(aq) + 3 H2O(l)

C) 3 NH4Cl(aq) + 3 OH–(aq) → 3 NH3(aq) + 3 H2O(l) + 3 Cl–(aq)

D) 3 NH4+(aq) + Fe(OH)3(s) → 3 NH3(aq) + 3 H2O(l) + Fe3+(aq)

E) no reaction

68) In a solution that is 0.50 M CH3COOH(aq) (acetic acid), the species with a concentration of

approximately 0.50 M is ________.

A) CH3COOH

B) C2H3O2–

C) H+

D) H+ and C2H3O2–

69) For the reaction between aqueous potassium hydroxide and aqueous nitric acid, the so-called

“spectator” ions are ________.

A) K+ and OH–

B) H+ and NO3–

C) K+ and NO3–

D) H+ and OH–

70) How many electrons are transferred when the perchlorate ion is converted to chloride?

A) 8

B) 7

C) 9

D) 6

E) 5

71) When the following equation is completed and balanced for the reaction in acidic aqueous solution,

what is the proper coefficient for H+?

Zn(s) + Cr2O72- (aq) → Zn2+ (aq) + Cr2+ (aq)

A) 22

B) 18

C) 14

D) 11

E) 7