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Question #45017

Difficulty: 8/10 | 🟢 Free

The Question

A concentration cell is constructed at 298 K298 \text{ K} using copper electrodes dipping into two aqueous solutions of copper(II) sulfate (\ceCuSO4\ce{CuSO4}):

\ceCu(s)∣CuSO4(aq,c1)∣∣CuSO4(aq,c2)∣Cu(s)\ce{Cu(s) | CuSO4 (aq, c_1) || CuSO4 (aq, c_2) | Cu(s)}

Due to significant ion pairing at higher concentrations, the salt does not behave ideally. The Van't Hoff factor (ii) for the left half-cell (c1=0.05 Mc_1 = 0.05 \text{ M}) is experimentally determined to be 1.801.80, while for the right half-cell (c2=0.40 Mc_2 = 0.40 \text{ M}) it is 1.401.40.

Assuming the effective concentration of \ceCu2+\ce{Cu^{2+}} ions is determined by the degree of dissociation (α\alpha) derived from the Van't Hoff factor, calculate the cell potential (EcellE_{\text{cell}}) in millivolts (mV).

(Given: 2.303RTF=0.06 V\frac{2.303 RT}{F} = 0.06 \text{ V}, log⁡2=0.30\log 2 = 0.30, log⁡3=0.48\log 3 = 0.48, log⁡7=0.84\log 7 = 0.84)

Options

  • A.

    +18 mV+18 \text{ mV}

  • B.

    +27 mV+27 \text{ mV}

  • C.

    +23.4 mV+23.4 \text{ mV}

  • D.

    +36 mV+36 \text{ mV}

Check Your Answer

Correct Answer

Step-by-Step Solution

Explanation

How the Examiner Thinks

Mechanism_Trap

Don't get tricked by the process! Learn the mechanical traps used in competitive exam questions.

Concepts Behind This Question

Nernstian Redox Equilibrium|Concentration Cells|Van’t Hoff Factor (i) Application

Why This Question Is Tricky

Common Mistakes

This problem tests the application of the Nernst equation in non-ideal solutions where molarity does not equal activity.

Students often blindly plug the given molarities (c1,c2c_1, c_2) into the Nernst equation, yielding +27 mV+27 \text{ mV}.

Another common trap is confusing the effective concentration of a specific ion with the total particle concentration used in colligative properties (i×ci \times c), which yields +23.4 mV+23.4 \text{ mV}.

By forcing the derivation of the degree of dissociation (α\alpha) from the Van't Hoff factor, the question evaluates a deep understanding of ionic equilibrium and electrochemistry.

Quick Facts About This Question

Question Information

SubjectChemistry
ChapterRedox Reactions - Class 11 Part 2
ConceptNernstian Redox Equilibrium
Difficulty8
Cognitive Load7
Target Solve Time160 sec
AccessFree