Education.com
Try
Brainzy
Try
Plus

Electrochemistry Multiple Choice Review Questions for AP Chemistry

based on 8 ratings
By — McGraw-Hill Professional
Updated on Feb 9, 2011

Review the following concepts if necessary:

Problems

Answer the following questions in 25 minutes. You may not use a calculator. You may use the periodic table at the back of the book.

Choose one of the following for questions 1–4.

  1. There is no change in the voltage.
  2. The voltage becomes zero.
  3. The voltage increases.
  4. The voltage decreases, but stays positive.
  5. The voltage becomes negative.
  6. The following reaction takes place in a voltaic cell.

    Zn(s) + Cu2+(1 M) → Cu(s) + Zn2+(1 M)

    The cell has a voltage that is measured and found to be +1.10 V.

  1. What happens to the voltage when a saturated ZnSO4 solution is added to the zinc compartment of the cell?
  2. What happens to the cell voltage when the copper electrode is made smaller?
  3. What happens to the cell voltage when the salt bridge is filled with deionized water instead of 1 M KNO3?
  4. What happens to the cell voltage after the cell has operated for 10 minutes?
  5. MnO4(aq) + H+(aq) + C2O42–(aq) → Mn2+(aq) + H2O(l) + CO2(g)
  6. What is the coefficient of H+ when the above reaction is balanced?

    1. 16
    2. 2
    3. 8
    4. 5
    5. 32
  7. S2O32– + OH → SO42– + H2O + e
  8. After the above half-reaction is balanced, which of the following are the respective coefficients of OH and SO42–in the balanced half-reaction?

    1. 8 and 3
    2. 6 and 2
    3. 10 and 2
    4. 5 and 2
    5. 5 and 1
  9. How many moles of Pt may be deposited on the cathode when 0.80 F of electricity is passed through a 1.0 M solution of Pt4+?
    1. 1.0 mol
    2. 0.60 mol
    3. 0.20 mol
    4. 0.80 mol
    5. 0.40 mol
  10. All of the following may serve as reducing agents, EXCEPT:
    1. Mg
    2. Cs
    3. Fe2+
    4. MnO4
    5. Br
  11. Cr2O72–– + 14 H+ +3 S2– → 2 Cr3+ + 3 S + 7 H2O
  12. For the above reaction, pick the true statement from the following.

    1. The S2– is reduced by Cr2O72–.
    2. The oxidation number of chromium changes from +7 to +3.
    3. The oxidation number of sulfur remains –2.
    4. The S2– is oxidized by Cr2O72–.
    5. The H+ oxidizes the S.
  13. H+ + NO3 + e → NO + H2O
  14. What is the coefficient for water arising when the above half-reaction is balanced?

    1. 3
    2. 4
    3. 2
    4. 1
    5. 6
  15. Co2+ + 2 e → Co E° = –0.28 V
  16. Cd2+ + 2 e → Cd E° = –0.40 V

    Given the above standard reduction potentials, estimate the approximate value of the equilibrium constant for the following reaction:

      Cd + Co2+ → Cd2+ + Co
    1. 10–4
    2. 10–2
    3. 104
    4. 1016
    5. 102
  17. When a basic solution of KMnO4 is added to an SnCl2 solution, a brown precipitate of MnO2 forms and Sn4+ remains in solution. When the same basic solution of KMnO4 is added to an NaF solution, no reaction occurs. Which of the substances involved in these reactions serves as the best reducing agent?
    1. SnCl2
    2. KMnO4
    3. NaF
    4. MnO2
    5. Sn4+
  18. A sample of silver is to be purified by electrorefining. This will separate the silver from an impurity of gold. The impure silver is made into an electrode. Which of the following is the best way to set up the electrolytic cell?
    1. an impure silver cathode and an inert anode
    2. an impure silver cathode and a pure gold anode
    3. a pure silver cathode with an impure silver anode
    4. a pure gold cathode with an impure silver anode
    5. an impure silver cathode with a pure silver anode
  19. 2 MnO4 + 16 H+ + 5 S2– → 2 Mn2+ + 5 S + 8 H2O
  20. The reducing agent in the above reaction is which of the following?

    1. MnO4
    2. H+
    3. S
    4. S2–
    5. Mn2+
  21. 2 Fe3+ + Zn → Zn2+ + 2 Fe2+
  22. The reaction shown above was used in an electrolytic cell. The voltage measured for the cell was not equal to the calculated E ° for the cell. This discrepancy could be caused by which of the following?

    1. The anion in the anode compartment was chloride, instead of nitrate as in the cathode compartment.
    2. One or more of the ion concentrations was not 1 M.
    3. Both of the solutions were at 25°C instead of 0°C.
    4. The solution in the salt bridge was Na2SO4 instead of KNO3.
    5. The anode and cathode were different sizes.
  23. How many grams of mercury could be produced by electrolyzing a 1.0 M Hg(NO3)2 solution with a current of 2.00 A for 3.00 h?
    1. 22.4 g
    2. 201 g
    3. 11.2 g
    4. 44.8 g
    5. 6.00 g
  24. An electrolysis cell was constructed with two platinum electrodes in a 1.00 M aqueous solution of KCl. An odorless gas evolves from one electrode, and a gas with a distinctive odor evolves from the other electrode. Choose the correct statement from the following list.
    1. The gas with the distinctive odor was evolved at the anode.
    2. The odorless gas was oxygen.
    3. The gas with the distinctive odor was evolved at the negative electrode.
    4. The odorless gas was evolved at the positive electrode.
    5. The odorless gas was evolved at the anode.
  25. H2O2(aq) + KIO4(aq) → KIO3(aq) + O2(g) + H2O(l)
  26. Choose the true statement from the following list.

    1. The iodine oxidation state is reduced from +8 to +6.
    2. This is not an oxidation–reduction reaction.
    3. H2O2 behaves as a reducing agent.
    4. Hydrogen is reduced from +2 to +1.
    5. H2O2 behaves as an oxidizing agent.

    Questions 19 and 20 are concerned with the following half-reaction in an electrolytic cell:

     

    2 BrO3 + 12 H+ + 10 e → Br2 + 6 H2O

  27. Choose the correct statement from the following list.
    1. The BrO3 undergoes oxidation at the anode.
    2. Br goes from a –1 oxidation to a 0 oxidation state.
    3. Br2 is oxidized at the anode.
    4. H+ is a catalyst.
    5. The BrO3 undergoes reduction at the cathode.
  28. If a current of 5.0 A is passed through the electrolytic cell for 0.50 h, how should you calculate the number of grams of Br2 that will form?
    1. (5.0)(0.50)(3600)(159.8)/(10)
    2. (5.0)(0.50)(3600)(159.8)/(96500)(10)
    3. (5.0)(0.50)(60)(159.8)/(96500)(10)
    4. (5.0)(0.50)(3600)(79.9)/(96500)(10)
    5. (5.0)(0.50)(159.8)/(96500)(10)
  29. 2 M(s) + 3 Zn2+(aq) → 2 M3+(aq) + 3 Zn2+(aq) E° = 0.90 V

    Zn2+(aq) + 2e → Zn(s) E° = –0.76 V

    Using the above information, determine the standard reduction potential for the following reaction:

    M3+(aq) + 3e→ M(s)

    1. 0.90 V
    2. +1.66 V
    3. 0.00 V
    4. –0.62 V
    5. –1.66V
View Full Article
Add your own comment

Ask a Question

Have questions about this article or topic? Ask
Ask
150 Characters allowed