Which of the following is true?
A)If we know that a reaction is an elementary reaction, then we know its rate law.
B)The rate-determining step of a reaction is the rate of the fastest elementary step of its mechanism.
C)Since intermediate compounds can be formed, the chemical equations for the elementary reactions in a multistep mechanism do not always have to add to give the chemical equation of the overall process.
D)In a reaction mechanism, an intermediate is identical to an activated complex.
E)all of these statements are true.

Answer:

If we know that a reaction is an elementary reaction, then we know its rate law.

Explanation:

An elementary reaction is a reaction that takes place in one reactive encounter. This means that the two species interact in a single step to give the products.

If two reactants interact in a single step to yield the products then we can easily deduce the rate law from the reaction equation.

For instance, For the reaction;

2A + B → C

The rate law is

rate = k[A]²[B].

If the reaction is an elementary reaction and the equation of the reaction is balanced, then we can deduce the rate law from the balanced reaction equation.