THE ANSWER OF VOLTAIC CELL QUIZ Part II

1.The equation that represents a reaction that is not a redox reaction is ….
1. Zn + CuSO4 → ZnSO4 + Cu
2. 2H2O2 → 2H2O + O2
3. H2O + CO2 → H2CO3
4. 2H2 + O2 → 2H2O
Answer (Reaction no. 3)
2.For the galvanic cell described below, the correct line notation is ….
Cl2 + 2e- → 2Cl- (E0 = 1.36v)
Cu+ + e- → Cu (E0 = 0.52v)
Answer : Pt(s)Cu(s)Cu+(aq)Cl2(g)2Cl-(aq)Pt(s)
3.What is indicated when a chemical cell's voltage (E) has dropped to zero?
Answer : The cell reaction has reached equilibrium.
4.Given the redox reaction:
2 Cr(s) + 3 Cu2+(aq) --> 2 Cr3+(aq) + 3 Cu(s)
Which reaction occurs at the cathode in an electrochemical cell?
Answer : reduction of Cu2+(aq)
5.Given the cell reaction:
2 H2O(l) --> 2 H2(g) + O2(g)
The cell is best described as ....
Answer : an electrolytic cell in which an endothermic reaction occurs
6.In an electrochemical cell, what is the purpose of the salt bridge?
Answer : It permits the migration of ions between the half-cells.
7.In a voltaic cell what type of ions move toward the cathode?
Answer : anions
8.What is the equation for the net cell reaction for the electrochemical cell:
Pb(s) PbI2(s) HI(aq) H2(g) Pt(s)
Answer : Pb(s) + 2HI(aq) --> PbI2(s) + H2
9.Referring to the table of Standard Cell Potentials below, determine the standard cell potential for the following reaction running in this direction:
2 Fe3+(aq) + Zn(s) --> 2 Fe2+(s) + Zn2+(aq)
Answer (+1.53 V)

STANDARD REDUCTION POTENTIALS E°(volts)
F2 + 2 e- ---> 2 F- Eo = +2.87 V
Au+ + e- ---> Au Eo = +1.69 V
Ag+ + e- ---> Ag Eo = +0.80 V
Fe3+ + e- ---> Fe2+ Eo = +0.77 V
Cu2+ + 2 e- ---> Cu Eo = +0.34 V
2 H+ + 2 e- ---> H2 Eo = 0 V
Pb2+ + 2 e- ---> Pb Eo = -0.13 V
Fe2+ + 2 e- ---> Fe Eo = -0.44 V
Zn2+ + 2 e- ---> Zn Eo = -0.76 V
Na+ + e- ---> Na Eo = -2.71 V
Li+ + e- ---> Li Eo = -3.05 V
10.Which of the following metal ions in aqueous solution is most easily oxidized to its aqueous ionic form?
Answer (Na)
11.Which metal is used as a coating on steel to limit corrosion?
Answer (Zn)
12.Given the nickel-cadmium battery reaction:
2 NiOOH + Cd + 2 H2O --> 2 Ni(OH)2 + Cd(OH)2
What occurs during discharge in the nickel-cadmium battery?
Answer : Ni3+ is reduced to Ni2+.
13.Referring to the table of standard cell potentials attached, determine the standard cell potential of the following reaction for the corrosion of iron in an acidic environment:
Fe(s) + 2 H+(aq) +1/2 O2(g) --> Fe2+(aq) + H2O(l)
Answer (Eo = +0.44 V)
14.Which ion in solution is most easily reduced to its elemental form?
Cu2+
15.In the alkaline energy cell the overall reaction is: Zn(s) + 2MnO2(s) + 2H2O ---> Zn(OH)2(s) + 2MnO(OH)(s). Which of the following half-reactions is taking place at the cathode?
2MnO2(s) +2 H2O + 2e- ---> 2MnO(OH)(s) + 2OH-(aq)
16.In the lead storage battery the product of both the cathode and anode reactions is?
Answer (PbSO4)
17.The fuel cell we discussed in class forms the following product:
Answer (H2O)
18.In an alkaline energy cell the overall cell reaction is as follows:
Zn(s) + 2 MnO2(s) + 2 H2O --> Zn(OH)2(s) + 2 MnO(OH)
Which of the following reactions is taking place at the cathode?
Answer : Zn(OH)2(s) + 2e- --> Zn(s) + 2 OH-(aq)
19.In a Nickel-Cadmium cell the following overall reaction is taking place:
Cd(s) + NiO2(s) + 2 H2O --> Cd(OH)2(s) + Ni(OH)3(s)
Which of the following half-reactions are taking place at the anode?
Answer : Cd(s) + 2 OH-(aq) --> Cd(OH)2(s) + 2e-