The standard reduction potential data at 25^oC is given below:
E^o (Fe³⁺ , Fe²⁺) = +0.77V;
E^o (Fe²⁺ , Fe) = -0.44V;
E^o (Cu²⁺ , Cu) = +0.34V;
E^o (Cu⁺ , Cu) = +0.52V;
E^o [O₂(g) + 4H⁺ + 4e^- $$\to$$ 2H₂O] = +1.23V;
E^o [O₂(g) + 2H₂O + 4e^- $$\to$$ 4OH^-] = +0.40 V
E^o (Cr³⁺ , Cr) = -0.74V;
E^o (Cr²⁺ , Cr) = -0.91V;

Match E^o of the redox pair in List – I with the values given in List – II and select the correct answer using the code given below the lists:

List - I
P. E^o (Fe³⁺ , Fe)
Q. E^o (4H₂O $$\leftrightharpoons$$ 4H⁺ + 4OH^-)
R. E^o (Cu²⁺ + Cu $$\to$$ 2Cu⁺)
S. E^o (Cr³⁺, Cr²⁺)

List - II
1. -0.18 V
2. -0.4 V
3. -0.04 V
4. -0.83 V

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 solubility product (K_sp; mol³ dm^–9) of MX₂ at 298 K based on the information available for the given concentration cell is (take 2.303 $$\times$$ R $$\times$$ 298/F = 0.059 V)

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 ∆G (kJ mol^–1) for the given cell is (take 1F = 96500 C mol^–1)

Consider the following cell reaction:
2Fe(s) + O₂(g) + 4H⁺(aq) $$\to$$ 2Fe²⁺ (aq) + 2H₂O (l); E^o = 1.67 V
At [Fe²⁺] = 10^-3 M, P(O₂) = 0.1 atm and pH = 3, the cell potential at 25^oC is