On the basis of the information available from the reaction,

4/3Al + O₂ $$ \to $$ 2/3Al₂O₃,   $$\Delta $$G = $$-$$ 827 kJ mol^$$-$$1 of O₂,

the minimum e.m.f. required to carry out an electrolysis of Al₂O₃ is
(F = 96500 C mol^$$-$$1)

The e.m.f. of a Daniell cell at 298 K is E₁.

When the concentration of ZnSO₄ is 1.0 M and that of CuSO₄ is 0.01 M, the e.m.f. changed to E₂. What is the relationship between E₁ and E₂?

In electrolysis of NaCl when Pt electrode is taken then H₂ is liberated at cathode while with Hg cathode it forms sodium amalgam

Standard electrode potentials are
Fe²⁺/Fe [E^o = $$-$$0.44] and
Fe³⁺/Fe²⁺[ E^o = 0.77];
If Fe²⁺, Fe³⁺ and Fe blocks are kept together, then