How many hours would be required for the electroplating of 50.0 g of platinum from a solution of [PtCl₆]^2-, using an average current of 8.50 A at an 80.0 % electrode efficiency?

Question

| General Chemistry 3

Accepted Answer

Faraday’s law of electrolysis:

m = $\frac{It}{F}$ x $\frac{M}{ν_{e}}$ x η

m = mass deposited as Pt (in g)
I = current (in A)
t = time (in s)
F = Faraday’s constant = 96485 C.mol^-1
M = molar mass (in g.mol^-1) ⇒ M_Pt = 195.1 g.mol^-1
ν_e = stoichiometric coefficient of the electrons in the half reaction equation
η = electrode efficiency

Half reaction: Pt⁴⁺ (aq) + 4 e^- → Pt (s) [ν_e = 4]

t =

\frac{mF}{I} \times \frac{ν_{e}}{M} \times \frac{1}{η}

t =

\frac{50.0 \times 96485}{8.50} \times \frac{4}{195.1} \times \frac{100}{80}

t = 4.04 hours

Exercise 3 | Electrochemistry

General Chemistry 3 - Exercise 3