Question 1
If an electrolysis plant operates its electrolytic cells at a total current of 1.2 × 106 amp, how long will it take to produce one metric ton (one million grams) of Mg(s) from seawater containing Mg2+? (1 faraday = 96,485 coulombs)
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1.8 h◦
1.8 days◦
55 min◦
0.92 h◦
0.46 yearQuestion 2
In order to determine the identity of a particular lanthanide metal (M), a voltaic cell is constructed at 25°C with the anode consisting of the lanthanide metal as the electrode immersed in a solution of 0.0594 M MCl3, and the cathode consisting of a copper electrode immersed in a 1.00 M Cu(NO3)2 solution. The two half-reactions are as follows:
M(s) → M3+(aq) + 3e–
Cu2+(aq) + 2e–→ Cu(s)
The potential measured across the cell is 2.64 V. What is the identity of the metal?
Reduction Half-Reaction | E° (V) |
Cu2+(aq) + 2e–→ Cu(s) | 0.34 |
Ce3+(aq) + 3e–→ Ce(s) | –2.336 |
Dy3+(aq) + 3e–→ Dy(s) | –2.295 |
Eu3+(aq) + 3e–→ Eu(s) | –1.991 |
Gd3+(aq) + 3e–→ Gd(s) | –2.279 |
Sm3+(aq) + 3e–→ Sm(s) | –2.304 |
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Ce◦
Eu◦
Dy◦
Gd◦
Sm
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Cell parts and their functions
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