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Electrochemistry question

2019 · 11 Jan · Shift 2 · Q11
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Electrochemistry question

2019 · 11 Jan · Shift 2 · Q11

JEE MainChemistryElectrochemistryMCQ+4 / −1
Given the equilibrium constant: KC of the reaction : CuCuCu(s) + 2Ag+Ag^+Ag+ (aq) →\to→ Cu2+Cu^{2+}Cu2+ (aq) + 2AgAgAg(s) is 10 ×\times× 1015, calculate the E cell0_{cell}^0cell0​ of this reaciton at 298 K [2.303 RTF{{RT} \over F}FRT​ at 298 K = 0.059V]
  1. A
    0.4736 mV
  2. B
    0.04736 V
  3. C
    0.4736 V
  4. D
    0.04736 mV
View written solutionFree

Correct answer: C

  1. Write the given reaction and identify nnn

The reaction is:

Cu(s)+2Ag+(aq)→Cu2+(aq)+2Ag(s)Cu(s) + 2Ag^+(aq) \to Cu^{2+}(aq) + 2Ag(s)Cu(s)+2Ag+(aq)→Cu2+(aq)+2Ag(s)

Number of electrons transferred:

  • Cu→Cu2++2e−Cu \to Cu^{2+} + 2e^-Cu→Cu2++2e−
  • 2Ag++2e−→2Ag2Ag^+ + 2e^- \to 2Ag2Ag++2e−→2Ag

So,

n=2n = 2n=2
  1. Use the relation between equilibrium constant and standard cell potential

At 298 K298\,K298K,

Ecell∘=0.059nlog⁡KE^\circ_{cell} = \frac{0.059}{n}\log KEcell∘​=n0.059​logK

Given:

K=10×1015=1016K = 10 \times 10^{15} = 10^{16}K=10×1015=1016

Thus,

log⁡K=log⁡(1016)=16\log K = \log(10^{16}) = 16logK=log(1016)=16
  1. Substitute the values
Ecell∘=0.0592×16E^\circ_{cell} = \frac{0.059}{2} \times 16Ecell∘​=20.059​×16 Ecell∘=0.0295×16=0.472 VE^\circ_{cell} = 0.0295 \times 16 = 0.472 \text{ V}Ecell∘​=0.0295×16=0.472 V
  1. Match with the nearest option

The calculated value is approximately:

Ecell∘≈0.47 VE^\circ_{cell} \approx 0.47\text{ V}Ecell∘​≈0.47 V

Among the given options, the closest is:

0.4736 V\boxed{0.4736\text{ V}}0.4736 V​

So, the correct option is C.

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