Chemical Kinetics Question 203
Question: For a reaction, $ X(g)\to Y(g)+Z(g) $ the half life period is 10 min. In What period of time would the concentration of X be reduced to 10% of original concentration [DCE 2004]
Options:
A) 20 min
B) 33 min
C) 15 min
D) 25 min
Show Answer
Answer:
Correct Answer: B
Solution:
$ {x_{(g)}}\to {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} $
$ =\frac{0.693}{10\ \min } $
$ =\frac{2.303}{t}\log \frac{a}{a/10} $
$ =\frac{0.693}{10}=\frac{2.303}{t}\log 10 $
$ \therefore \ \ t=\frac{2.303\times 10}{.693}=33\min $ .
