Build a voltaic cell with one beaker containing potassium permanganate (KMnO4 ) solution with a platinum electrode and a second beaker containing zinc chloride with a zinc electrode. Determine:
a. The half reactions
b. Flow of electrons
c. Short-form notation
d. Electric potential (voltage)
Solution.
a.
(A): "Zn^{2+} + 2e = Zn^0"
(K): "MnO4^- + 2 H2O + 3e = MnO2 + 4OH^-"
b.
Electrons move from the anode (zinc) to the cathode (platinum).
c.
"Zn(s)|Zn^{2+}(aq)||MnO4^-(aq)|Pt(s)"
d.
"\\Delta E = E(k)-E(a)"
"\\Delta E = 0.6 - (-0.763) = 1.363 \\ V"
Answer:
a.
(A): "Zn^{2+} + 2e = Zn^0"
(K):"MnO4^- + 2 H2O + 3e = MnO2 + 4OH^-"
b.
Electrons move from the anode (zinc) to the cathode (platinum).
c.
Zn(s)|Zn^{2+}(aq)||MnO4^-(aq)|Pt(s)
d.
"\\Delta E = 1.363 \\ V"
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