Assertion: Order and molecularity are the same.
Reason: Order is determined experimentally, and molecularity is the sum of the stoichiometric coefficients of the rate-determining elementary step.
Assertion is incorrect but reason is correct.
Analysing the assertion
The order and the molecularity of a reaction may or may not be the same, as the order of a reaction is determined experimentally. They are equal for elementary one-step reactions, but for complex reactions, they may be different.
So, the assertion is an incorrect statement.
Analysing the reason
Only for elementary reactions, the order and the molecularity can be the same. For complex reactions, they may be different.
Order is determined experimentally, and molecularity is the sum of the stoichiometric coefficients of the rate-determining elementary step.
So, the reason is a correct statement.
Thus, the assertion is an incorrect statement, but the reason is a correct statement.
Hence, the correct answer is option (E).