question_answer 27)

Show that the time required for 99% completion of a reaction is twice the time required complete 90% of the reaction. 

Answer:

For a first order reaction; Ist case: a = 100%, x = 99%; (a ? x) = (100 ? 99) = 1% IInd case: a = 100%; x = 90% (x ? x) = (100 ? 90) = 10% Dividing eqn. (ii) by eqn. (i),