Electrochemical (Galvanic or Voltaic) Cells Worksheet
1. a) Determine the anode, cathode and calculate the standard cell potential produced by a galvanic cell
consisting of a Ni electrode in contact with a solution of Ni2+ ions and a Ag electrode in contact with
a solution of Ag1+ ions.
Ni2+(aq) + 2e- ⇌ Ni(s)
Ag+(aq) + e- ⇌ Ag(s)
E° = -0.26 V (lesser  flip)
E° = +0.80 V
Ni(s) ⇌ Ni2+(aq) + 2eCATHODE: 2 Ag+(aq) + 2e- ⇌ 2 Ag(s)
ANODE:
E° = +0.26 V
E° = +0.80 V
E° = +1.06 V
b) Write the shorthand cell notation.
Ag (s) | Ag1+ (aq) || Ni2+ (aq) | Ni (s)
2. a) Determine the anode, cathode and calculate the voltage produced by a galvanic cell consisting of an
Fe electrode in contact with a solution of Fe2+ ions and a Al electrode in contact with a solution of
Al3+ ions.
Fe2+(aq) + 2e- ⇌ Fe(s)
Al3+(aq) + 3e- ⇌ Al(s)
E° = -0.44 V
E° = -1.66 V (lesser  flip)
2 Al(s) ⇌ 2 Al3+(aq) + 6eCATHODE: 3 Fe2+(aq) + 6e- ⇌ 3 Fe(s)
ANODE:
E° = +1.66 V
E° = -0.44 V
E° = +1.22 V
b) Write the shorthand cell notation.
Fe (s) | Fe2+ (aq) || Al3+ (aq) | Al (s)
3. a) Determine the anode, cathode and calculate standard cell potential produced by a galvanic cell
consisting of a C electrode in contact with an acidic solution of ClO4- ions and a Cu electrode in
contact with a solution of Cu2+ ions. Which is anode and which is the cathode?
ClO4-(aq) + 8H+(aq) + 8e- ⇌ Cl-(aq) + 4H2O(l)
Cu2+(aq) + 2e- ⇌ Cu(s)
E° = +1.39 V
E° = +0.34 V (lesser  flip)
4 Cu(s⇌ 8 Cu2+(aq) ) + 8eCATHODE: ClO4-(aq) + 8H+(aq) + 8e- ⇌ Cl-(aq) + 4H2O(l)
ANODE:
b) Write the shorthand cell notation.
C (s) | ClO4- , H+ (aq) || Cu2+ (aq) | Cu (s)
E° = -0.34 V
E° = +1.39 V
E° = +1.05 V
4. An electrochemical cell is constructed using electrodes based on the following half reactions:
Pb2+ (aq) + 2e- ⇌ Pb(s)
Au3+(aq) + 3e- ⇌ Au(s)
a) Which is the anode and which is the cathode in this cell?
ANODE: Pb
CATHODE: Au
b) What is the standard cell potential?
ANODE:
CATHODE:
3 Pb(s) ⇌ 3 Pb2+(aq) + 6e2 Au3+(aq) + 6e- ⇌ 2 Au(s)
E° = +0.13 V
E° = +1.50 V
E° = +1.63 V
5. Use complete half-reactions and potentials to predict whether the following reactions are spontaneous or
non-spontaneous in aqueous solutions. If the cell is spontaneous, write the cell shorthard notation.
a) Ca2+(aq) + 2 I-(aq)  Ca(s) + I2(aq)
2 I-(aq) ⇌ I2(aq) + 2eCATHODE: Ca2+(aq) + 2e- ⇌ Ca(s)
ANODE:
E° = - 0.54 V
E° = - 2.87 V
E° = - 3.41 V
E° is negative, therefore the cell is non-spontaneous.
b) 2 H2S(g) + O2(g)  2 H2O(l) + 2 S(s)
H2S(g) ⇌ 2 S(s) + 2H+(aq) + 2eCATHODE: O2(g) + 4H+(aq) + 4e- ⇌ 2 H2O(l)
ANODE:
E° = - 0.14 V
E° = +1.23 V
E° = +1.09 V
E° is positive, therefore the cell is spontaneous.
C (s) | O2 (g) , H+ (aq) || H2S (g) ; S (g) | Pt (s)
c) SO2(g) + MnO2(s)  Mn2+(aq) + SO42-(aq)
ANODE:
SO2(g) + 2 H2O(l)⇌ SO42-(aq) + 4H+(aq) + 2eCATHODE: MnO2(s) + 4H+(aq) + 2e- ⇌ Mn2+(aq) + 2 H2O(l)
E° is positive, therefore the cell is spontaneous.
C (s) | MnO2(s) , H+(aq) ; Mn2+(aq) || SO2(g) ; SO42-(aq) | Pt (s)
d) 2 H+(aq) + 2 Br-(aq)  H2(g) + Br2(aq)
ANODE:
2 Br-(aq) ⇌ Br2(l) + 2eCATHODE: 2 H+(aq) + 2e- ⇌ H2(g)
E° = -1.07 V
E° = 0.00 V
E° = -1.07 V
E° is negative, therefore the cell is non-spontaneous.
E° = - 0.18 V
E° = +1.22 V
E° = +1.04 V
e) Ce4+(aq) + Fe2+(aq)  Ce3+(aq) + Fe3+(aq)
ANODE:
Fe2+(aq) ⇌ Fe3+(aq)+ eE° = - 0.77 V
CATHODE: Ce4+(aq) + e- ⇌ Ce3+(aq)
E° = +1.61 V
E° = - 2.38 V
E° is negative, therefore the cell is non-spontaneous.
f) Cr2+(aq) + Cu2+(aq)  Cr3+(aq) + Cu+(aq)
ANODE:
Cr2+(aq) ⇌ Cr3+(aq)+ eE° = +0.41 V
CATHODE: Cu2+(aq) + e- ⇌ Cu+(aq)
E° = +0.15 V
E° = +0.56 V
E° is positive, therefore the cell is spontaneous.
C (s) | Cu2+ (aq) ; Cu+(aq) || Cr2+ (aq) ; Cr3+(aq) | C (s)