A Cr3+(aq) solution is electrolyzed, using a current of 7.80 A .
1. What mass of Cr(s) is plated out after 1.50 days?
2.What amperage is required to plate out 0.200 mol Cr from a Cr3+
solution in a period of 7.00 h ?
1) 7.80A = 7.80 Coulomb per second
Coulomb in 1.50 days = 129600 × 7.80 = 1010880C
No of mole of electron = 1010880/96485 = 10.477
No of mole of electron required to deposit 1mol of Cr = 3
No of mole of Cr3+ deposited = 10.477/3= 3.4923
molar mass of Cr = 51.996g/mol
Mass of Cr plated = 51.996g/mol × 3.4923mol = 181.59g
2) mole of Cr plated out = 0.200mol
mole of electron required = 3×0.2 = 0.6mol
Coulombs required = 0.6 × 96485 = 57891C
plating period = 7 hours = 25200seconds
Amperage required = 57891/25200=2.297A
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