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Electrochemistry II: Electrolytic Cells 111
E"(Sn4+, Sn2+) = 0.15 V and E"(Fe3+, Fe2+) = 0.77 V and
F = 96500Cmol-'.
(a) +60 (b) 120 (c) -60 (d) -120
7. In the electrolysis of molten sodium chloride, how many of the
following statements are incorrect?
* Only sodium cations are reduced;
* Chlorine gas is evolved at the cathode;
* Hydrogen gas is generated at the anode;
* Chlorine gas is evolved at the anode.
(a) All4 (b) 3 (4 2 (4 1
8. The volume of hydrogen gas in dm3 measured at 1 bar and
298 K, evolved by a current of 8 mA flowing for a period of 25
days, through a concentrated aqueous hydrochloric acid elec-
trolysis cell is:
(a) 2.22 (b) 4.44 (c) 214272 (d)2220
(F = 96 500 C mol-' and 1 mol of an ideal gas at 1 bar pressure
and 298 K occupies 24.8 dm3).
9. How many of the following equations are incorrect?
Q = ItE"; E& = EEHE - E",,,; m = ZIT; AG = -nFE;
(a) All4 (b) 3 (c) 2 (d) 1
10. How many of the following electrodes will cause hydrogen gas
to be generated when they are coupled with a hydrogen
electrode to form an electrochemical cell?
E"(Fe2+, Fe) = -0.44 V; E"(Ag+, Ag) = +0.80 V;
E"(Ca2+, Ca) = -2.87 V; E"(Sn4+, Sn2+) = 0.15 V.
(a) 4 (b) 3 (c) 2 (4 1

LONG QUESTIONS ON CHAPTERS 6 AND 7

1. Give a fully labelled diagram of a galvanic cell based on the
following reaction:

PbS04(s) + 2FeS04(aq) Fe2(SO4)3(aq) + Pb(s)
If the cell is short-circuited, indicate the direction of current,
electron flow and ion flow. Label clearly the anode, the cathode,
and give the electrode and cell reactions. Given that
Eo(PbIPbS041S0:-) = -0.36 V, E"(Fe3+, Fe2+) = +0.77 V
and F = 96 500 C mol- ', comment on the spontaneity of the
cell. Explain your answer, by calculating the value of AGO.
2. Draw the Daniel cell. Determine the potential of the cell at
25 "C, in which the molar concentration of the Zn2+ ions is
0.22 M and that of the Cu2+ ions is 0.003 M, given that