Question

How many Faradays of electricity are required to deposit 10 g of calcium from molten calcium chloride using inert electrodes?
(molar mass of calcium = 40 g mol–1)

Answer 1

1 F deposit eq.mass

1F = >> 40÷2=20 gms

So 10 gms needs 0.5 faraday

Hope its useful to u

Have a good day

Answer 2

Answer : The number of Faradays of electricity required are, 0.5 F

Explanation : Given,

Mass of calcium = 10 g

Molar mass of calcium = 40 g/mole

First we have to calculate the moles of calcium.

$\text{Moles of calcium}=\frac{\text{Mass of calcium}}{\text{Molar mass of calcium}}=\frac{10g}{40g/mole}=0.25mole$

Now we have to calculate the number of Faradays of electricity are required.

As we know that if 'n' electrons are involved in the reaction, the passage of 'n' faradays (n × faraday) of electricity will liberate one mole of the substance.

The balanced reaction will be,

$Ca^{2+}+2e^-\rightarrow Ca$

As, 1 mole of calcium requires = 2 F

So, 0.25 mole of calcium requires = $0.25\times 2F=0.5F$

Therefore, the number of Faradays of electricity required are, 0.5 F