Question

Assertion :Passage of 48,250 coulombs of electricity through cupric sulphate and ferrous sulphate solutions result in the deposition 0.5 moles each of iron and copper at the respective cathodes. Reason: Number of equivalents of a metal deposited at cathode is equal to the number of faradays of electricity passed through the electrolyte.

• A. Both Assertion and Reason are correct and Reason is the correct explanation for Assertion
• B. Both Assertion and Reason are correct but Reason is not the correct explanation for Assertion
• C. Assertion is correct but Reason is incorrect
• D. Assertion is incorrect but Reason is correct

Answer 1

The correct option is D Assertion is incorrect but Reason is correct

Faraday's first law of electrolysis states that only,

According to this law, the chemical deposition due to a flow of current through an electrolyte is directly proportional to the quantity of electricity (coulombs) passed through it.

i.e. a mass of chemical deposition, m is proportional to Quantity of electricity 'Q'.

m = Z . Q

Where Z is a constant of proportionality and is known as an electrochemical equivalent of the substance.
48,250 coulombs is equal to 0.5 Faraday. A number of equivalents of metal deposited is equal to the number of faradays of electricity passed through the electrolyte that means 0.5 equivalents of copper and iron are deposited. Since they are bivalent ions, 0.5 equivalents correspond to 0.25 moles.
Thus Option D is correct.