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

Cell reaction is spontaneous when

Equivalent conductances of Ba²⁺ and Cl^$$-$$ ions are 127 and 76 ohm^$$-$$1 cm^$$-$$1 eq^$$-$$1 respectively. Equivalent conductance of BaCl₂ at infinite dilution is

For the disproportionation of copper
2Cu⁺  $$ \to $$ Cu²⁺ + Cu, E^o is
(Given E^o for Cu²⁺/Cu is 0.34 V and
E^o for Cu²⁺/Cu⁺ is 0.15 V.)