Question

How many moles of solid chromium can be deposited from a crcl3 solution when a steel wrench is electroplated with a current of 3.0 amps for 965 seconds? do this without a calculator?

Answer 1

According to Faraday's Law,

W = I t e / F
Where,
W = Amount deposited = ?
I = Current = 3 A
t = Time = 965 s
e = Chemical equivalence = 52/3 = 17.33
F = Faraday's Constant = 96500
Putting Values,
W = (3 × 965 × 17.33) ÷ 96500
W = (50170.35) ÷ 96500
W = 0.52 g
As we know,
Moles = mass ÷ M.mass
Putting values,
Moles = 0.52 ÷ 52

Moles = 0.01