For a first-order reaction, the time required for 75 % completion is 40 minutes . The time required for 93.75 % completion of the same reaction will be:

Step-by-step solution

For a first-order reaction, the amount of reactant remaining after n half-lives is given by N₀ 2^n . At 75 % completion, the amount remaining is 100 % - 75 % = 25 % . Since 25 % = 1 4 = ( 1 2 )^2 , this corresponds to 2 half-lives. Therefore, 2 t_ 1/2 = 40 minutes t_ 1/2 = 20 minutes . At 93.75 % completion, the amount remaining is 100 % - 93.75 % = 6.25 % . Since 6.25 % = 6.25 100 = 1 16 = ( 1 2 )^4 , this corresponds to 4 half-lives. The time required is 4 t_ 1/2 = 4 20 minutes = 80 minutes . Assuming a linear re