2.21 A variable-order reaction, described in eqn 2.64, with a half saturation constant of 50 mg/L and a rate constant of 4.0 mg L1hr' occurs in a batch reactor. If the initial concentration is 500 mg/L how long is required to achieve a 75% completion? Which is a more reasonable approximation of this reaction at this initial concentration - first order or zero order?

Fig: 1