Question

When a quantity of electricity is passed through CuSO₄ solution, 0.16 g of copper gets deposited. If the same quantity of electricity is passed through acidulated water, then the volume of H₂ liberated at STP will be: (given atomic weight of Cu=64).
Option
A.56 cm³
B.8 cm³
C.12 cm³
D.604 cm³

Answer 1

Hint: Copper sulphate, with the formula CuSO₄, is a chemical compound that can be produced in a chemistry lab by reacting copper oxide with sulphuric acid. Copper sulphate has a variety of applications, including as a fungicide and herbicide in agriculture, as well as in fireworks and copper plating.

Complete answer:
The Second Law of Electrolysis by Faraday.
”The masses of different molecules are equal to their equivalent masses as they are liberated or dissolved by the same volume of electricity.” The masses of the various materials liberated or dissolved at the corresponding electrodes are in the ratio of their equivalent masses while the same amount of electricity is transferred through multiple electrolytic solutions connected in sequence.
\[\dfrac{{{\text{ Weight of Cu deposited }}}}{{{\text{ Weight of }}{{\text{H}}_2}{\text{ produced }}}} = \dfrac{{{\text{ Eq}}{\text{. wt of Cu}}}}{{{\text{ Eq}}{\text{. wt of H}}}}\]
\[\dfrac{{{\text{ Weight of Cu deposited }}}}{{{\text{ Weight of }}{{\text{H}}_2}{\text{ produced }}}} = \dfrac{{{\text{ Eq}}{\text{. wt of Cu}}}}{{{\text{ Eq}}{\text{. wt of H}}}} = \dfrac{{\dfrac{{64}}{2}}}{1}\]
\[\dfrac{{0.16}}{{{{\text{w}}_{{{\text{H}}_2}}}}} = \dfrac{{32}}{1}\]
\[\text { mass of } H_{2} \text { liberated }=\dfrac{0.16}{32} g=5 \times 10^{-3} g\]
Volume of hydrogen liberated at STP
Volume = 56 cm³

Hence, option A is correct.

Note:
The abbreviation STP stands for Standard Temperature and Pressure in chemistry. STP is most widely found in measurements involving gases, such as gas density. The standard temperature is 273 K (0 ºC or 32 ° C), and the standard pressure is 1 atm.