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JEE Main Chemistry Electrochemistry 2026 JEE Main 2026 (24 January Shift 1)

JEE Main Chemistry Question (2026) — Solution

Question

Electricity is passed through an acidic solution of Cu ^ 2+ till all the Cu ^ 2+ was exhausted, leading to the deposition of 300 mg of Cu metal. However, a current of 600 mA was continued to pass through the same solution for another 28 minutes by keeping the total volume of the solution fixed at 200 mL. The total volume of oxygen evolved at STP during the entire process is \_\_\_\_ mL. (Nearest integer) [Given: Cu ^ 2+ ( aq )+2 e ^ - Cu ( s ) E _ red ^ o =+0.34 ~V O _ 2 ( ~g )+4 H ^ + +4 e ^ - 2 H _ 2 O E _ red ^ o =+1.23 ~V Molar mass of Cu =63.54 ~g ~mol ^ -1 Molar mass of O _ 2 =32 ~g ~mol ^ -1 Faraday Constant =96500 C mol ^ -1 Molar volume at STP =22.4 ~L ]

Options

  1. A. A
  2. B. B
  3. C. C
  4. D. D

Answer

A. A

Step-by-step solution

Eq of Cu = Eq of O_2 300 10^ -3 2 63.54 = n_ O_2 4 2.36 10^ -3 = n_ O_2 When current is further passed n_ O_2 4 = 600 28 60 96500 1000 n_ O_2 = 2.611 10^ -3 Total O_2 released = [10^ -3 (2.36 + 2.611)] 22400 ml = 111.35 ml

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