The half-life period of a first-order chemical reaction is 6.93 min. The time required for the completion of 99% of the chemical reaction will be (log 2 = 0.301)

Half-life = 6.93 min, k1=0.6936.93=0.1 min−1Rate constant for the first-order reaction is given byk=2.303tlog⁡[A0][A]Where [A0]=initial concentration [A]=final concentration 0.1=2.303t×log⁡10010.1=2.303t×log⁡102t=2.3030.1×2log⁡10=46.06 min