Redox Quiz #3 Balancing Redox reactions- Acid & Base Cell Potentials


1. Consider the following overall reaction:

2Rh+ + Pb(s) 2Rh(s) + Pb2+- E0 = 0.73 V

The E0 for the half-reaction Rh+ + e- Rh is

A. -0.86 V

B. -0.60 V

C. +0.60 V

D. +0.86 V


2. Which of the following systems would be correct if the zinc half-cell would have been chosen as the

            standard instead of the hydrogen half-cell?

A. The reduction potentials of all the half-cells would remain unchanged

B. The reduction potentials of all the half-cells would increase by 0.76 V

C. The reduction potentials of all the half-cells would have positive values

D. The reduction potentials of the hydrogen half-cell decrease by 0.76 V


3. Three beakers contain 1.0 M CuCl2. A piece of metal is placed in each of the
















Reactions occur in

A beaker 2 only

B. beakers 1, 2, and 3

C. beakers 1 and 2 only

D. beakers 1 and 3 only


4. Consider the following redox reaction:

3SO2 + 3H2O + ClO3- → 3SO42- + 6H+ + Cl-

The reduction half-reaction is

A. ClO3- + 6H+Cl- + 3H2O + 6e-

B. ClO3- + 6H+ + 6e-Cl - + 3H2O

C. SO2 + 2H2O → SO42- + 4H+ + 2e-

D. SO2 + 2H2O + 2e- → SO42- + 4H+


5. What two substances are produced when Cr and 1.0 M MnO4- react in a basic solution?

A. Mn2+ and Cr3+

B. MnO2 and Cr3+

C. Mn2+ and Cr2+

D. MnO2 and CrO42-


6. Bromine, Br2, will react spontaneously with

A. I-

B. I2

C. Cl-

D. Cl2


7. The substances H2O2, H3PO4 and H2SO3 in order of increasing strengths as

oxidizing agents are.

A H2O2, H3PO4, H2SO3

B. H2SO3, H3PO4, H2O2

C. H3PO4, H2SO3 , H2O2

D. H2O2,H2SO3 , H3PO4


8. Consider the following overall equation for an electrochemical cell:

3Ag+ + Cr → Cr3+ + 3Ag

At standard conditions ,the initial cell voltage is

A. +0.06 V

B. +0.39 V

C. +1.21 V

D. +1.54


9. A solution of 1.0 M Co(NO3)2 should be stored in a container made of

A. tin

B. zinc

C. aluminum

D. magnesium


10. A strong oxidizing agent has a

A. weak attraction for electrons

B. strong attraction for electrons

C. weak ability to become reduced

D. strong ability to become oxidized


11. The two species which react spontaneously in acidic solutions are

A. IO3- and I2

B. SO42- and S

C. BrO3- and Br -

D. AuCl4- and Au


12. Consider the following redox reaction:

Co2+(aq) + 2Ag(s) → 2Ag+(aq) + Co(s)

The reaction is

A. spontaneous and Eo is positive.

B. spontaneous and Eo is negative.

C. non-spontaneous and Eo is positive.

D. non-spontaneous and Eo is negative

13. Referring to the data booklet, which of the following can act as an oxidizing agent but not as a reducing agent?

A. Zn

B. Cl-

C. Sn2+

D. Fe3+


14. Which equation represents a redox reaction?

A. Pb2+ + 2Cl- → PbCl2

B. CaO + CO2 → CaCO3

C. Mg + 2HCl → MgCl2 + H2

D. HCl + NaOH → NaCl + H2O


15. In a redox reaction, ClO- was converted to Cl- in a basic solution. The balanced half-reaction for this process is


A. ClO- + H2O + 2e-Cl- + 2OH-

B. ClO- + 2OH-Cl- + 2e- + H2O

C. ClO- + H2O → Cl- + 2e- + 2OH-

D. ClO- + 2OH- + 2e-Cl- + H2O


16. Which of the following gives the correct oxidation numbers for the nitrogen atoms in all three chemical species?

N2 Li3N NO2-

A. 0 -3 +3

B. -3 -3 +3

C. 0 +3 -3

D. -3 -3 -3


17. The oxidation number of manganese changes as MnO4- is converted to MnO2. How many electrons are gained or

            lost by the manganese during the change?

A. 1e- lost

B. 1e- gained

C. 3e- lost

D. 3e- gained

18. Which of the solutions listed below should NOT be stored in a tin-plated container?
I NaNO3(aq) II AgNO3(aq) III SnBr2(aq) IV Cl2(aq)
A. I only
B. II and IV
C. II, III and IV
D. II and III

19. If fluorine gas is bubbled through NaI(aq),

A. Na+(aq) is reduced
B. I-(aq) is oxidized
C. F2(aq) is oxidized
D. I-(aq) is reduced

20. A high school laboratory's waste container is used to dispose of aqueous

solutions of sodium nitrate, potassium sulfate, hydrochloric acid, and tin (II)

chloride. The most likely net redox reaction predicted to occur inside the waste

container is represented by the equation:

A. Sn2+(aq) + 2NO3-(aq) + 4H+(aq) 2NO(g) + 2H2O(l) + Sn4+(aq)
B. 2 H+(aq) + 2K+(aq) H2(g) + K(s)
C. SO42-(aq) + 4H+(aq) + 2 Cl-(aq) H2SO3(aq) + H2O(l) + Cl2(g)
D. Cl2(g) + Sn2+(aq) Cl-(aq) + Sn(s)

21. The net ionic equation for the reaction between aqueous solutions of tin (II)

bromide and iron (III) nitrate is

A. Sn2+(aq) + NO3-(aq) NO2(g) + Sn4+(aq)
B. Sn2+(aq) + 2 Fe3+(aq) Sn4+(aq) + 2 Fe2+(aq)
C. 2Sn2+(aq) + Fe3+(aq) 2 Sn3+(aq) + Fe2+(aq)
D. Sn2+(aq) + 2NO3-(aq) 2NO2(g) + Sn4+(aq

22. Use the following unbalanced redox reaction to answer this question.

__O2(g) + ___H+(aq) + ___Ag(s) __Ag+(aq) + ___H2O(l)

The coefficients for the balanced equation are
A. 1,4,4,4,2
B. 1,4,1,1,2
C. 1,2,1,1,1
D. 1,1,1,1,1

23. A student mixes various combinations of the metals Pd, Cd and Ga with 1.0 M

solutions of their ions. The student then measures the voltages and puts them in

the table below.

1 Ga Pd2+ +1.18 V

2 Ga Cd2+ +0.16 V

3 Cd Pd2+?

What voltage is produced by reaction # 3?

A. -1.34 V

B. -1.02 V

C. +1.02 V

D. +1.34 V


24. Which of the following is a correctly balanced reduction half-reaction?

A. 2HCN + 2e- C2N2 + 2H+

B. 2Sb + 3H2O + 6e- Sb2O3 + 6H+

C. NO3- + 3H+ + 3e- HNO2 + H2O

D. Sb2O5 + 6H+ + 4e- 2Sb(OH)2+ + H2O



25. Which of the following combinations will react spontaneously under standard


A. Ag + Br2

B. Ni + Co2+

C. Zn + Mg2+

D. Au + HNO3


26. Which of the following best describes what happens when lead solid is placed in a

1.0 M solution of Cu(NO3)2?

A. Bubbles form on the lead.

B. No changes are observed.

C. Copper solid forms on the lead and the solution changes colour.

D. The mass of lead solid increases and the solution does not change colour.


27. Consider the following unbalanced equation for a redox reaction in acidic

solution: Br- + BrO3- Br2

What is the equation for the balanced reduction half-reaction?

A. 2Br- Br2 + 2e-

B. 2Br- + 2e- Br2

C. 5e- + 6H+ + 2BrO3- Br2 + 3H2O

D. 10e- + 12H+ + 2BrO3- Br2 + 6H2O


28. What reaction will occur when a solution containing 1.0 M MgSO4 and 1.0 M

CoCl2 is stored in a galvanized (Zn coated) bucket?

A. Mg(s) + Cl2 MgCl2(s)

B. Co2+ + SO42- CoSO4(s)

C. Co2+ + Zn(s) Zn2+ + Co(s)

D. Mg2+ + Zn(s) Zn2+ + Mg(s)


29. When the skeletal equation I- IO3- is balanced in acidic solution, H2O, H+

and e- will appear. Which of the following are the correct balancing coefficients?

H2O H+ e-


A. 3 3 2

B. 3 6 6

C. 3 6 5

D. 6 12 10


30. Consider the following balanced redox equation in acidic solution:

5H2O + 2CoCl2 + OCl- 2Co(OH)3 + 5Cl- + 4H+

Which of the following describes the amounts and locations of OH- and H2O if

the equation is balanced in basic solution?

A. 1H2O on the left and no OH-

B. 1H2O on the left and 4OH- on the left

C. 5H2O on the left and 4OH- on the left

D. 1H2O on the left and 4OH- on the right