Q. For a reaction,$x(g) \rightarrow y(g) + z(g)$ the half-life period is 10 min. in what period of time would the concentration of X be reduce to 10% of original concentration?

A) 20 min
B) 33 min
C) 15 min
D) 25 min
Explanation

(b)
$X(g) \rightarrow Y(g) + Z(g)$
The reaction is a first order reaction.
Hence ,
$k = \frac{0.693}{t_{1/2}} = \frac{2.303}{t}\log\frac{a}{(a - x)}$
$02234\ \frac{0.693}{10} = \frac{2.303}{t}\log\frac{a}{a/10}$
Or $t = \frac{2.303 \times 10}{0.693} \times \log 10$
=33min

Dr. Abubacker
Reviewed by Dr. Abubacker

Physics Educator & NEET/JEE Specialist

Ph.D. in Physics with 19+ years of teaching experience.