Name
No:
Homework 5
1- Complete and balance the following redox equation using the smallest wholenumber coefficients. What is the coefficient of Sn in the balanced equation?
Sn + HNO3  SnO2 + NO2 + H2O (acidic solution)
A. 1
B. 2
C. 3
D. 4
E. 5
2- Complete and balance the following redox equation. What is the coefficient of H2S
when the equation is balanced using the set of smallest whole-number
coefficients?
H2S +MnO4- Mn2+ + SO42- (acidic solution)
A. 1
B. 2
C. 4
D. 5
E. none of these
3- Complete and balance the following redox equation. What is the coefficient of H2O
when the equation is balanced with the set of smallest whole-number
coefficients?
H2O +MnO4- + I- MnO2 + IO3- (basic solution)
A. 1
B. 2
C. 4
D. 10
E. none of these
4- Given the following notation for an electrochemical cell
Pt(s) | H2(g) | H+(aq) || Ag+(aq) | Ag(s),
what is the balanced overall (net) cell reaction?
A.
B.
C.
D.
E.
2H+(aq) + 2Ag+(aq)  H2(g) + 2Ag(s)
H2(g) + 2Ag(s)  H+(aq) + 2Ag+(aq)
2H+(aq) + 2Ag(s)  H2(g) + 2Ag+(aq)
H2(g) + Ag+(aq)  H+(aq) + Ag(s)
H2(g) + 2Ag+(aq)  2H+(aq) + 2Ag(s)
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Name
No:
Homework 5
5- Consider an electrochemical cell constructed from the following half cells, linked
by a KCl salt bridge.
 an Al(s) electrode in 0.5 M Al2(SO4)3 solution
 a Pb(s) electrode in 1.0 M Pb(NO3)2 solution
Which electrode is the anode?
A. Al
B. Pb
C. neither
6- Consider an electrochemical cell constructed from the following half cells, linked
by a KCl salt bridge.
 a Fe electrode in 1.0 M FeCl2 solution
 a Ni electrode in 1.0 M Ni(NO3 )2 solution
When the cell is running spontaneously, which choice includes only true
statements and no false ones?
D.
A. The nickel electrode loses mass and the nickel electrode is the cathode.
B. The nickel electrode gains mass and the nickel electrode is the cathode.
C. The iron electrode gains mass and the iron electrode is the anode.
The iron electrode loses mass and the iron electrode is the cathode
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Name
7-
No:
Homework 5
Calculate the value of Ecell for the following reaction:
2Au(s) + 3Ca2+(aq)  2Au3+(aq) + 3Ca(s)
A. -4.37 V
B. -1.37 V
C. -11.6 V
D. 1.37 V
E. 4.37 V
8- For the reaction, 2Cr2+ + Cl2(g)  2Cr3+ + 2Cl-, Ecell is 1.78 V. Calculate Ecell for
the related reaction Cr3+ + Cl-  Cr2+ + (1/2)Cl2(g).
A. 1.78 V
B. 0.89 V
C. -1.78 V
D. -0.89 V
E. none of these
9- The overall reaction 2Co3+(aq) + 2Cl-(aq)  2Co2+(aq) + Cl2(g) has the standard
cell voltage Ecell= 0.46 V.
Given that Cl2(g) + 2e-  2Cl-(aq), E = 1.36 V,
calculate the standard reduction potential for the following the half reaction at
25C:
Co3+ + e-  Co2+
A. 1.82 V
B. -0.90 V
C. 0.90 V
D. -1.82 V
E. -1.36 V
10- Which statement is true for a spontaneous redox reaction carried out at standardstate conditions?
A.
B.
C.
D.
Ered is always negative.
Ecell is always positive.
Eox is always positive.
Ered is always positive.
3