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JEE Mains · Chemistry · STD 12 - 2. Electrochemistry

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 :
\(Cu ^{2+}( aq )+2 e ^{-} \rightarrow Cu ( s ) E _{\text {red }}^0=+0.34 V\)
\(O _2(g)+4 H ^{+}+4 e ^{-} \rightarrow 2 H _2 O E _{ red }^0=+1.23 V\)
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 \(S T P=22.4 L\) ]

  1. A 55
  2. B 222
  3. C 111
  4. D 148
Verified Solution

Answer & Solution

Correct Answer

(C) 111

Step-by-step Solution

Detailed explanation

Eq of \( Cu = Eq \) of \( O_{2} \) \(\frac{300 \times 10^{-3} \times 2}{63.54}= n _{ O _2} \times 4\) \(2.36 \times 10^{-3}= n _{ O _2}\) When current is further passed \(n _{ O _2} \times 4=\frac{600 \times 28 \times 60}{96500 \times 1000}\) \(n _{ O _2}=2.611 \times 10^{-3}\)…
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