Copper reduces NO$$_3^ - $$ into NO and NO₂ depending upon the concentration of HNO₃ in solution. (Assuming fixed [Cu²⁺] and P_NO = P_NO2), the HNO₃ concentration at which the thermodynamic tendency for reduction of NO$$_3^ - $$ into NO and NO₂ by copper is same is 10^x M. The value of 2x is _______. (Rounded off to the nearest integer)

[Given, $$E_{C{u^{2 + }}/Cu}^o = 0.34$$ V, $$E_{NO_3^ - /NO}^o = 0.96$$ V, $$E_{NO_3^ - /N{O_2}}^o = 0.79$$ V and at 298 K, $${{RT} \over F}$$(2.303) = 0.059]

The magnitude of the change in oxidising power of the $$MnO_4^ - /M{n^{2 + }}$$ couple is x $$\times$$ 10^$$-$$4 V, if the H⁺ concentration is decreased from 1M to 10^$$-$$4 M at 25$$^\circ$$C. (Assume concentration of $$MnO_4^ - $$ and $$M{n^{2 + }}$$ to be same on change in H⁺ concentration). The value of x is ___________. $$\left[ {Given\,:{{2.303RT} \over F} = 0.059} \right]$$

Potassium chlorate is prepared by the electrolysis of KCl in basic solution

6OH^- + Cl^- $$ \to $$ ClO₃^- + 3H₂O + 6e^-

If only 60% of the current is utilized in the reaction, the time (rounded to the nearest hour) required to produce 10 g of KClO₃ using a current of 2 A is_________.

(Given : F = 96,500 C mol^–1; molar mass of KCIO₃ = 122 g mol^–1)

An oxidation-reduction reaction in which
3 electrons are transferred has a $$\Delta $$Gº of 17.37 kJ mol^–1 at
25 ^oC. The value of E^o
cell (in V) is ______ × 10^–2.
(1 F = 96,500 C mol^–1)