Eduprobe
Question:
The electrochemical cell shown below is a concentration cell. M|M²⁺(saturated solution of a sparingly soluble salt, MX₂)||M²⁺(0.001 mol dm⁻³)|M The emf of the cell depends on the difference in concentrations of M²⁺ ions at the two electrodes. The emf of the cell at 298 K is 0.059 V. The value of ΔG (kJ mol⁻¹) for the given cell is: [take 1F = 96500 C mol⁻¹]
5.7
-9.7
-11.4
11.4
Solution:
At cathode: M²⁺(aq) + 2e⁻ → M(s)
At anode: M(s) + 2X⁻(aq) → MX₂(aq) + 2e⁻
n-factor of the cell reaction is 2.
ΔG = -nFEcell = -2 × 96500 × 0.059 = -11.4 kJ mol⁻¹