If the rate of the reaction is equal to the rate constant, the order of the reaction is

The reaction A $$ \to $$ B follows first order kinetics. The time taken for 0.8 mole of A to produce 0.6 mole of B is 1 hour. What is the time taken for conversion of 0.9 mole of A to produce 0.675 mole of B?

The activation energy for a simple chemical reaction A $$\rightleftharpoons$$ B is E_$$a$$ in forward direction.
The activation energy for reverse reaction

2A $$ \to $$ B + C

It would be a zero order reaction when