How many coulombs of electrical charge must pass through an electrolytic cell to reduce (check my answer)?

Question

How many coulombs of electrical charge must pass through an electrolytic cell to reduce 0.82 moles of Ca2+ ion to calcium metal?

a) 3.9e3
b) 1.6e5
c) 7.9e4
d) 4.2e–6
e) 4.0e4

I got b, 96500 x 2 = 193000 x .82 = 158260 ...im not sure Im doing this right...

Answer 1

The answer is b however I don't quite follow your reasoning

Faraday's constant is approximately 96500 coulomb/mole of electrons

Each Ca2+ needs 2 electrons so 0.82 mole Ca2+ need 2*0.82 mole of elecrons, so a total charge of 2*0.82*F=2*0.82*96500= 1.6*10^5