Under the same reaction conditions, the initial concentration of 1.386 mol dm−3 of a substance becomes half in 40 s and 20 s through first order and zero order kinetics, respectively.
The ratio (k1/k0 of the rate constants for first order (k1) and zero order (k0)of the reaction is
For the first order reaction, rate constant
k1=0.693t1/2=0.69340
For zero order reaction, rate constant
k0=A02×t1/2=1.3862×20
Hence,
k1k0=0.6931.386=0.5