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Question: Answered & Verified by Expert
The half life period of a first order reaction is 1 $\min 40$ secs. Calculate its rate constant.
ChemistryChemical KineticsJEE Main
Options:
  • A $6.93 \times 10^{-3} \mathrm{~min}^{-1}$
  • B $6.93 \times 10^{-3} \mathrm{sec}^{-1}$
  • C $6.93 \times 10^{-3} \mathrm{sec}$
  • D $6.93 \times 10^{3} \mathrm{sec}$
Solution:
1163 Upvotes Verified Answer
The correct answer is: $6.93 \times 10^{-3} \mathrm{sec}^{-1}$
For $1^{\text {st }}$ order reaction.
$\mathrm{t}_{1 / 2} \text { (halflife time) }=\frac{0.693}{\mathrm{~K}}$
Hence $\mathrm{K}=\frac{0.693}{\mathrm{t}^{1 / 2}}=\frac{0.693}{(60+40) \mathrm{sec}}=0.693 \times$ $10^{-2} \mathrm{sec}^{-1}=6.93 \times 10^{-3} \mathrm{sec}^{-1}$

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