Question

A current liberated 0.50 g of hydrogen in 2 hours. How many grams of copper can be liberated by the same current flowing for the same time in CuSO₄ solution?

Options

• 12.7 g

• 15.9 g

• 31.8 g

• 63.5 g

Answer 1

15.9 g

Explanation:

According to Faraday’s second law of electrolysis, the masses of different substances liberated by the same quantity of electricity are proportional to their chemical equivalents.

Equivalent mass of hydrogen = 1

Equivalent mass of copper = `63.5/2` = 31.75

Mass of hydrogen = 0.50

Now,

`"Mass of Cu"/"Mass of H" = "Equivalent mass of Cu"/"Equivalent mass of H"`

`"Mass of Cu"/0.50 = 31.75/1`

Mass of Cu = 0.50 × 31.75

= 15.875 g

≈ 15.9 g