CoachIn the steady-state approximation (or quasi-steady state), the concentration of a very reactive intermediate, consumed much faster than it is formed, is taken as constant and small after a short induction period: its rate of formation equals its rate of consumption, .
![Consecutive reactions A B C. Left: the intermediate accumulates and peaks at k_1t = 1.39. Right: when it is consumed twenty times faster than it forms, it stays small and follows the steady-state value k_1[ A]/k_2 (dashed) after a brief induction.](/images/onecourse/chapters/chemistry-2/b1-elementary-steps/fig-48ec13f91136.svg)