Voltaic Cell

Ni²⁺ + 2e à Ni  E^o = -0,25 V

Pb²⁺ + 2e à Pb E^o = -0,13 V

The standard potential of a voltaic cell consisting of Ni and Pb electrodes is…

•    -0,38 V

•    -0,03 V

•   +0,12 V

•    +0,25 V

• +0,38 V

Mg²⁺ (aq) + 2e à Mg (s) E^o = -2,37 volt

Sn²⁺ (aq) + 2e à Sn(s) E^o = -0,14 volt

With these data, voltaic cells are arranged. Which of the following statements is true…

•    Mg metal as cathode

•   Reaction: Sn + Mg²⁺ à Mg + Sn²⁺ is spontaneous

•    The resulting cell potential is +2.57 volts

• Sn metals acts as a positive electrode

• Soluble Sn eelectrode

From the following standard electrode potential data

Cu²⁺ + 2e à Cu  E^o = +0,34 volt

Ag⁺ + e à Ag     E^o = +0,80 volt

Then the Cu + 2Ag reaction has a cell potential...

•   0,06 v

• 0,46 v

•   0,57 v

•   1,14 v

• 1,26 v

Knowing :

Cu²⁺  + 2e^- à Cu  E^o = +0,34 volt

Mg²⁺ + 2e^- à Mg  E^o + -2,34 volt

Zn²⁺ + 2e^- à Zn  E^o = -0,76 volt

Al³⁺ + 3e^- à Al  E^o = -1,66 volt

Fe²⁺ + 2e^- à Fe  E^o = -0,44 volt

The greatest value of cell potential is found in...

• Cu |Cu²⁺ || Al³⁺ |Al

•   Al | Al³⁺ || Zn²⁺ |Zn

• Mg |Mg²⁺ || Cu³⁺ |Cu

•   Zn |Zn²⁺ || Fe²⁺ |Fe

• Fe |Fe³⁺ || Cu²⁺ |Cu

If the metal reduction potential is known as follows: X²⁺ + 2e^- à X  E^o = +0,47 volt

Y²⁺ + 2e- à Y E^o = -0,76 volt

Z²⁺ + 2e^- à Z  E^o = -0,83 volt

The arrangement of the metals X, Y, and Z in the voltaic series in order of increasing reducing strength...

• X-Y-Z

• Y-X-Z

• Z-Y-X

• X-Z-Y

• Y-Z-X

Car batteries have Pb and PbO₂ electrodes. When the battery produces an electric current, a change occurs....

• Pb becomes PbSO₄, while PbO₂ remains

• Pb becomes PbO and PbO₂ becomes Pb₃O₄

• Pb and PbO₂ both become PbSO₄

• Pb become Pb₃O₄, and PbO₂ becomes PbO

• Pb and PbO both become PbO

A simple battery can be made to dissolve 2 tablespoons of table salt per 200 cc of water, this solution is used as an electrolyte, while zinc and copper are used as electrodes. The most appropriate reason this cell is called an air zinc battery is….

•  A copper plate is used as a cathode so that it is positively charged

•  The zinc plate is used as the anode so it is negatively charged

• After a while of use, a black layer forms on the zinc electrode

•  Oxygen from the air reacts with zinc, while the copper electrode functions to drain electrons

• The electrolyte of table salt reacts with air so that the zinc electrode forms a black layer

Look at the following voltaic cell picture!

Knowing :

E^o : Zn²⁺/Zn = -0,76 V

E^o : Cu²⁺/Cu = +0,34 V

                 

The following statements are ini accordance with the voltaic cell picture above, except…

• Eelectrons flow from the Zn electrode to the Cu electrode.

• Zn metal acts as anode

• The resulting cell potential is 1.10 volt

• At the cathode, Cu²⁺ ions are reduced

• The salt bridge can be replaced by conducting wire

   

Five groups of elements A, B, C, D and E are known. From the experiment, the following data were obtained: Metal B is the strongest reducing agent. Metal A and C can reduce D2+ ions to D, but cannot reduce E²⁺. Metal C can reduce ions A2+ becomes A. The order of increasing standard electrode potential values is ….

• A-B-C-D-E

• E-D-C-B-A

• B-C-A-D-E

• B-E-C-A-D

• B-E-D-A-C

Note some facts about the following battery:

(1) Wrap in the battery in the form of zinc (Zn) as the positive electrode

(2) Carbon rod (C) as cathode

(3) Electrolyte using MnO₂ and NH₄Cl . paste

(4) Oxidation reaction occurs in zinc metal

(5) Reduction reaction takes place on the outer carbon and zinc

Which statement is true about battery cells as dry cells?

• 1,2,3

• 2,3,4

• 2,3,5

• 1,2,4

• 3,4,5