I----A standard galvanic cell is constructed with Fe 3+ | Fe 2+ and Mn 2+ | Mn h
ID: 990672 • Letter: I
Question
I----A standard galvanic cell is constructed with Fe3+|Fe2+ and Mn2+|Mn half cell compartments connected by a salt bridge. Which of the following statements are correct?
Hint: Refer to a table of standard reduction potentials.
(Choose all that apply.)
--The anode compartment is the Fe3+|Fe2+ compartment.
--In the external circuit, electrons flow from the Fe3+|Fe2+ compartment to the Mn2+|Mn compartment.
Fe2+ is oxidized at the anode.
--The cathode compartment is the Fe3+|Fe2+ compartment.
--As the cell runs, anions will migrate from the Fe3+|Fe2+ compartment to the Mn2+|Mn compartment
II--A standard galvanic cell is constructed in which a Cu2+ | Cu+ half cell acts as the cathode. Which of the following statements are correct?
Hint: Refer to a table of standard reduction potentials.
(Choose all that apply.)
-The anode compartment could be Br2|Br-.
-In the external circuit, electrons flow from the other compartment to the Cu2+|Cu+ compartment.
-Cu+ is oxidized at the cathode.
-As the cell runs, anions will migrate from the other compartment to the Cu2+|Cu+ compartment.
-Cu2+ is reduced at the cathode.
C---Use standard reduction potentials to calculate the standard free energy change in kJ for the reaction:
Answer: kJ
K for this reaction would be _________(greater,less) than one.
Explanation / Answer
1. The cathode compartment is the Fe3+|Fe2+ compartment.
As the cell runs, anions will migrate from the Fe3+|Fe2+ compartment to the Mn2+|Mn compartment
2. In the external circuit, electrons flow from the other compartment to the Cu2+|Cu+ compartment.
Cu2+ is reduced at the cathode.
3.
2H+(aq) + 2I-(aq)Arrow.gifH2(g) + I2(s)
E0cell = E0c - E0a
= 0.54 - 0 = 0.54 V
DG0 = -nFE0cell = -2*96500*0.54 = -104.22 kj
DG0 = -RTlnK
-104.22*10^3 = -8.314*298lnk
K = 1.856*10^18
K for this reaction would be greater than one.