An endothermic reaction with high activation energy for the forward reaction is given by the diagram.

The activation energy for a simple chemical reaction $\mathrm{A}\to \mathrm{B}$, is ${\mathrm{E}}_{\mathrm{a}}$ in the forward direction. The activation energy for the reverse reaction 

Activation energy of a chemical reaction can be determined by

The activation energy for a simple chemical reaction $\mathrm{A}\to \mathrm{B}$, is ${\mathrm{E}}_{\mathrm{a}}$ in the forward direction. The activation energy for the reverse reaction.

Assertion: The rate law of a reaction cannot be predicted from its balanced chemical equation, but must be determined experimentally only.

Reason: The order of a reaction is always an integer like $0, 1, 2$and $3$.

[TS EAMCET (med.) 2015]

Which one of the following statement is not correct for the order of the reaction?

[IIT JEE 2005; CBSE PMT (Prelims) 2011]