Question

How many Faradays of electricity are required to deposit 20 g of calcium from molten calcium chloride using inert electrodes?
(Molar mass of calcium = 40 g mol⁻¹)

Options

• 0.5 F

• 1 F

• 0.25 F

• 2 F

Answer 1

1 F

Explanation:

\[\ce{Ca^{2+} + 2e^- -> Ca}\]

2 F will deposit 1 mole Ca (i.e., 40 g of Ca)
Hence, 1 F of electricity will be required to deposit 20 g of Ca from molten CaCl₂ when inert electrodes are used.