CHEMISTRY · Single correct · A Level · Chemistry · Introduction to organic chemistry · Introduction to organic chemistry
Problem
In the study of reaction mechanisms, which statement best defines a reaction intermediate?
(a) A species that lowers the activation energy of a reaction and is regenerated unchanged, so it appears in both the first and last elementary steps
(b) A short-lived high-energy arrangement of atoms present at the maximum of the potential-energy profile for an elementary step
(c) A species that is formed in one elementary step and consumed in a later elementary step, so it cancels and is absent from the overall balanced equation
(d) A reactant in the overall balanced equation that momentarily increases in concentration during a fast pre-equilibrium before being used up in the slow step