Question

10g fairly concentrated solution of $CuS{O_4}$ is electrolysed using 0.01 faraday of electricity. Calculate the mass of the resulting solution.
a.) 7.6025g
b.) 9.6025g
c.) 6.6025g
d.) 77.6025g

Answer 1

Hint: In order to deal with this question first we will write the reaction of the given compound then we will proceed further by applying Faraday's law so that we will get 1 faraday current and by substituting the obtained mass with initial mass we will get the required answer.
Formula used- $W = ZQ$, where $Q = I \times t = current \times time$

Complete step by step answer:
Given that the Initial solution weight is 10g.
Reaction formed:
At anode: $C{u^{ + 2}} + 2{e^ - } \to Cu$

At cathode: $2{H_2}O \to 4{H^ + } + {O_2} + 4{e^ - }$
According to Faraday's law,
$W = ZQ$,
And $Q = I \times t = current \times time$
Where Z is electrochemical equivalent
And W is the weight of the substance
From the given equations we have:
So, 1 faraday deposits 0.5 mole of Cu.
1 faraday current deposit $\dfrac{{63.5}}{2}g = 31.75g$ of copper
So, 0.01 faraday current deposit $31.75 \times 0.01 = 0.3175g$of copper
Initial solution weight is 10g.
Therefore, after electrolysis weight of the solution is $10g - 0.3175g = 9.6825g \approx 9.6025g$
Hence the mass of the resulting solution is 9.6025g
So, the correct answer is “Option B”.

Additional Information:
 Copper sulphate is used in both agricultural and non-agricultural environments as a fungicide, algaecide, root-killer and herbicide. This is used also as an antimicrobial and molluscicide. Uses for individual copper-sulphate products differ greatly.

Note: Electrolysis, method of passing electrical current through a material to induce a chemical transition. The chemical transition is one where the material loses an electron (oxidation or reduction) or retains one. The procedure is carried out in an electrolytic cell, a device composed of positive and negative electrodes isolated and dipped into a solution containing ions that are charged positively and negatively. The material to be converted may represent the electrode, may be the solution, or may be dissolved in the solution.