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

When a bio-chemical reaction is carried out in laboratory, outside the human body in absence of enzyme, then rate of reaction obtained is 10^$$-$$6 times, the activation energy of reaction in the presence of enzyme is

For the reaction;

2N₂O₅ $$ \to $$ 4NO₂ + O₂ rate and rate constant are 1.02 $$ \times $$ 10^$$-$$4 and 3.4 $$ \times $$ 10^$$-$$5 sec^$$-$$1 respectively, then concentration of N₂O₅ at that time will be

Correct order of 1^st ionization potential among following elements Be, B, C, N, O is