Q. The time taken for the completion of 3/4 of a first order reaction is
A) $(2.303/k)\log{3/4}$
B) $(2.303/k)\log 4$
C) $(2.303/k)\log{1/4}$
D) $(2.303/0.75)\log k$
Explanation
(b)
$t = \frac{2.303}{k}\log\frac{a}{a - x}$
$\because x = \frac{3}{4}\ a$
$\therefore\ t = \frac{2.303}{k}\log\frac{a}{a - \frac{3}{4}\ a}$
$= \frac{2.303}{k}\log 4$
Reviewed by Dr. Abubacker
Physics Educator & NEET/JEE Specialist
Ph.D. in Physics with 19+ years of teaching experience.