Question

Faraday¡¯s Law of Electrolysis
• Practice Problem.
• What is the oxidation state of the osmium atom
in an unknown salt if 26.7 grams of osmium plate
out when a current of 15 amps is passed through
a solution of this salt for 1 hour?

Answer 1

Coulombs = A x seconds = 15 x 60 x 60 = 54000.
1F = 96,485 coulombs will plate out 190.2g/valence.

You had 54,000 C which is
54,000/96485 C = 0.5597 moles.
moles x valence/molar mass = 26.7*valence/190.2 = 0.5597
Solve for valence . My calculator reads 3.98 which I would round to 4.