Question

A certain current liberate 0.5 g of hydrogen in 2 h. How many grams of copper can be liberated by the same current flowing for the same time in a copper sulphate solution ?

• A. 12.7 gm
• B. 15.9 gm
• C. 318 gm
• D. 63.5 gm

Answer 1

Answer: (A)

12.7 gm

Answer 2

$0.5\, g = \frac{0.5}{2}$ mol of $H_2$ $0.25$ mol of $H_2$ is liberated by electricity $= 2 \times 96500 \times 0.25\, C$ $Cu$ liberated by $2 \times 96500 \times 0.25 \,C$ $= \frac{2\times 96500 \times 0.25}{2\times 96500} = 0.2\,mol$ Amount of $Cu = 0.2 \times 63.5 = 12.7 \,g$