Q. For the first order reaction half-life is 14 s, the time required for the initial concentration to reduce to 1/8 of its value is
A) $(14)^{3}s$
B) 28 s
C) 42 s
D) $(14)^{2}s$
Explanation
(c)
$N = N_{0} \times \left( \frac{1}{2} \right)^{n}$
$\frac{1}{8}N_{0} = N_{0} \times \left( \frac{1}{2} \right)^{n}$
N=3
$T = n \times t_{1/2}$
=$3 \times 14$=42s
Reviewed by Dr. Abubacker
Physics Educator & NEET/JEE Specialist
Ph.D. in Physics with 19+ years of teaching experience.