A current of 15.0 A is passed through molten magnesium chloride for 15.0 h.How many moles of magnesium metal could be produced via this electrolysis?
A) 0.0700 mol
B) 4.20 mol
C) 0.37 mol
D) 0.22 mol
E) 8.40 mol

Question

Quizplus · Accepted Answer

The amount of charge passed through the electrolyte is calculated as:

Q = I × t
Q = 15.0 A × (15.0 h × 3600 s/h)
Q = 1.62 × 10^6 C

The factor that relates the amount of charge passed to the amount of substance produced is the Faraday constant (F):

1 F = 96,485 C/mol

So the number of moles of magnesium produced can be calculated as:

n = Q/F
n = 1.62 × 10^6 C/96,485 C/mol
n = 16.8 mol

However, we need to consider that each magnesium ion (Mg2+) requires 2 electrons to be reduced to a magnesium atom, so the amount of moles of magnesium produced will be half of the amount of moles of charge passed:

n(Mg) = 0.5 × n
n(Mg) = 0.5 × 16.8 mol
n(Mg) = 8.40 mol

Therefore, the answer is B: 4.20 mol.

A Current of 15