Conversion of Reversible to Unidirectional Reactions

An often useful approach is to eliminate the elements of reversibility from a reaction and force it to completion, either by the use of a large excess of reactant or by rapid removal of one of the products. A good illustration is afforded by the study of 

Since the equilibrium quotient K is small, a nonnueleophilic base is added to the reaction mixture to react with liberated protons and drive the reaction to completion (left to right). Using an excess of ROH then ensures simple unidirectional pseudo first-order (rate constant Atj) kinetics  

The reverse reaction also gives simple first-order (rate eonstant k,) kinetics when studied with excess HCIO4  

It was verified that A ,/A i equaled AT, determined in a separate experiment. For another example, see Ref. 53. 

The reversible first-order reaction (1.47) can be converted into an irreversible A X process by scavenging X rapidly and preventing its return to A. Thus the intramolecular reversible electron transfer in modified myoglobin (Sec. 5.9) 

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