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In the given electrochemical cell, Ag ( s )| AgCl ( s )| FeCl ₂( aq ), FeCl ₃( aq ) Pt ( s ) at 298 K, the cell potential ( E _ cell ) will increase when : A. Concentration of Fe ²⁺ is increased. B. Concentration of Fe ³⁺ is decreased. C. Concentration of Fe ²⁺ is decreased. D. Concentration of Fe ³⁺ is increased. E. Concentration of Cl ⁻ is increased. Choose the correct answer from the options given below :

Options

  1. AB Only
  2. BA and E Only
  3. CC, D and E Only
  4. DA and B Only

Correct answer

C. C, D and E Only

Step-by-step solution

The cell Ag(s)|AgCl(s)|FeCl₂(aq), FeCl₃(aq)|Pt(s) has the reaction: Ag(s) + Cl⁻ + Fe³⁺ → AgCl(s) + Fe²⁺ Using Nernst equation: E_ cell = E°_ cell - 0.059 n Q where Q = [Fe²⁺] [Fe³⁺][Cl^-] For E_ cell to increase, Q must decrease. Analyzing each condition: A. Increase [Fe²⁺] increases Q, decreases E_ cell - false B. Decrease [Fe³⁺] increases Q (smaller denominator), decreases E_ cell - false C. Decrease [Fe²⁺] decreases Q, increases E_ cell - true D. Increase [Fe³⁺] decreases Q, increases E_ cell - true E. Increase

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