The half-life of a substance in a certain enzyme-catalysed reaction is 138 ~s . The time required for the concentration of the substance to fall from 1.28 mg L ⁻¹ to 0.04 mg L ⁻¹ is

Step-by-step solution

Enzyme-catalysed reactions follow first order kinetics. aligned & 1.28 t_ 1 / 2 0.64 t_ 1 / 2 0.32 t_ 1 / 2 0.16 & t_ 1 / 2 0.08 t_ 1 / 2 0.04 aligned aligned Time required & =5 t_ 1 / 2 & =5 138 ~s & =690 ~s . aligned