For the following reactions
$$A\buildrel {700K} \over \longrightarrow {\mathop{\rm Product}\nolimits} $$
$$A\mathrel{\mathop{\kern0pt\longrightarrow} \limits_{catalyst}^{500K}} {\mathop{\rm Product}\nolimits} $$
it was found that E_a is decreased by 30 kJ/mol in the presence of catalyst.
If the rate remains unchanged, the activation energy for catalysed reaction is (Assume pre exponential factor is same):

Consider the following plots of rate constant versus $${1 \over T}$$ for four different reactions. Which of the following orders is correct for the activation energies of these reactions?

The rate of a certain biochemical reaction at physiological temperature (T) occurs 10⁶ times faster with enzyme than without. The change in the activation energy upon adding enzyme is :

For the reaction
2H₂(g) + 2NO(g) $$ \to $$ N₂(g) + 2H₂O(g)
the observed rate expression is, rate = K_f[NO]²[H₂]. The rate expression for the reverse reaction is :