Chemical Kinetics Question 206
Question: The rate of a first order reaction is $ 1.5\times {10^{-2}}\ mol{L^{-1}}\ {{\min }^{-1}} $ at 0.5 M concentration of the reactant. The half life of the reaction is [CBSE PMT 2004]
Options:
A) 8.73 min
B) 7.53 min
C) 0.383 min
D) 23.1 min
Show Answer
Answer:
Correct Answer: D
Solution:
Rate $ ( \frac{dx}{dt} )=K\ .\ c $ ; $ 1.5\times {10^{-2}}=K\times 0.5 $ For first order $ K=\frac{1.5\times {10^{-2}}}{0.5}=3\times {10^{-2}}\min ut{e^{-1}} $
$ {t_{1/2}}=\frac{.693}{K}=\frac{.693}{3\times {10^{-2}}}=23.1\ \min ute $ .
