Question 16 of 29advanced🔧 ApplyNumerical5 marks

Calculate the standard cell potentials of galvanic cell in which the following reactions take place: (i) 2Cr(s) + 3Cd²⁺(aq) → 2Cr³⁺(aq) + 3Cd (ii) Fe²⁺(aq) + Ag⁺(aq) → Fe³⁺(aq) + Ag(s). Calculate the ΔrG° and equilibrium constant of the reactions.

(i)
Answer

Standard Cell Potential (E°cell): 0.34 V

ΔrG°: -197 kJ mol⁻¹

Equilibrium Constant (K): 3.67×103.67 \times 10³⁴

(ii)
Answer

Standard Cell Potential (E°cell): 0.03 V

ΔrG°: -2.9 kJ mol⁻¹

Equilibrium Constant (K): 3.2

Explanation

This question requires calculating standard cell potentials using electrode potentials from Table 3.1, then applying thermodynamic relationships. For reaction (i), Cr is oxidized (anode) and Cd²⁺ is reduced (cathode), with n=6 electrons transferred. For reaction (ii), Fe²⁺ is oxidized and Ag⁺ is reduced, with n=1 electron transferred. The formulas ΔrG° = -nFE°cell and ΔrG° = -RT ln K are applied using F = 96487 C mol⁻¹ and T = 298 K as shown in the textbook examples.

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