Question

Nickel can be plated from aqueous solution according to the following half reaction. How long would it take (in minutes) to plate 29.6g of Nickel at 4.7A?

Ni^2+ (aq) + 2e- --> Ni(s)

Answer 1

First, calculate moles of Nickel required

mol = mass/MW = (29.6)/58.6934 = 0.504315 moles of Ni(s) required

so

1 mol of Ni(s) requires 2 mol of e-

0.504315 mol of Ni = 2*0.504315 = 1.00863 mol of e- required

now,

1 mol of e- = 96500 C (Faraday constant)

1.00863 mol of e- = (1.00863)(96500) = 97332.795 C

recall that

Current = Charge / time

Current = 4.7 A = 4.7 C/sec

4.7 C/s = 97332.795 C / t

t = 97332.795 / (4.7) = 20709.105 seconds

we need minutes fo

1 min = 60 s

20709.105 /60 = 345.15 minutes