Competitive Exams: Chemistry MCQs (Practice-Test 15 of 31)

  1. A galvanic cell is constructed from a half cell containing a solid copper electrode in 1.0 M Cu (NO3) 2 solution and a half cell containing a solid aluminum electrode in 1.0 M Al (NO3) 3 solution at standard conditions. The half cells are linked by an external circuit and by a KCl salt bridge.

    1. N/A

    2. N/A

    3. N/A

    4. N/A

  2. The balanced overall (net) cell reaction for a spontaneous process is:

    1. Cu (s) + Al3 + (aq) → Cu2 + (aq) + Al (s)

    2. 3 Cu (s) + 2 Al3 + (aq) → 3 Cu2 + (aq) + 2 Al (s)

    3. 3 Cu2 + (aq) + 2 Al (s) → 3 Cu (s) + 2 Al3 + (aq)

    4. Cu2 + (aq) + Al (s) → Cu (s) + Al3 + (aq)

    5. The reaction is not spontaneous.

  3. Which of the following statements is TRUE about this cell?

    1. The aluminum electrode is the anode; the copper electrode is the cathode.

    2. The electrons flow from the copper electrode to the aluminum electrode.

    3. The cell diagram is |Cu solid|Cu2 +, 1.0 M|salt bridge|Al solid|Al3 +, 1.0 M|

    4. G is greater than zero.

    5. S is the driving force of this reaction.

  4. This cell generates a standard potential of:

    1. + 1.32 V

    2. -2.00 V

    3. -1.32 V

    4. + 2.00 V

    5. The cell is at equilibrium.

  5. An expression for the equilibrium constant of this reaction at 25oC is:

    1. e205

    2. e298

    3. e467

    4. e831

    5. e965

  6. You have installed a new hot water heater in your house, and you notice that the iron tank has a large metal bar bolted to it on the inside. You conclude that this bar is a sacrificial anode and that it could be made of:

    1. Ag

    2. Ni

    3. Pb

    4. Sn

    5. Mg

  7. We used copper and zinc electrodes stuck in an apple to run a small clock. Which of the following statements must be TRUE?

    1. The zinc strip was the anode

    2. The apple was the salt bridge

    3. Ecell > 0

    4. G < 0

    5. All of these statements are true