The rate law for a gas-phase reaction at is Which of the following best explains why…
CHEMISTRY · Single correct · A Level · Chemistry · Rate equations · Rate equations
Problem
The rate law for a gas-phase reaction at 298K is
rate=k[A]2[B]
Which of the following best explains why this rate law alone suggests that the process is unlikely to occur in a single elementary collision?
(a) The squared concentration term shows that two A molecules react consecutively, so at least two separate elementary steps are required.
(b) For a third-order reaction, the units of the rate constant k would be unusual, indicating the process cannot be a single collision.
(c) Simultaneous collision of three gas molecules, 2A+B, is exceedingly improbable under ordinary conditions.
(d) Elementary reactions are limited to first- or second-order overall; a third-order rate law must result from a multistep mechanism.