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  • what percentage of the substrate will remain offer 2 hours If the half life of a first order reaction is 30 minutes.Option: 1 <img alt="3 \cdot 75 \%

what percentage of the substrate will remain offer 2 hours If the half life of a first order reaction is 30 minutes.

Option: 1

3 \cdot 75 \%


Option: 2

9.5 \%


Option: 3

6.25 \%


Option: 4

12 \cdot 5 %


Answers (1)

best_answer

for a first order Reaction \mathrm{t_{1/2}=\frac{0.693}{K}}
\mathrm{K=\frac{0.693}{t_{1 / 2}}=\frac{0.693}{30}=0.0231 \mathrm{~min}^{-1}}
To find the \mathrm{%}. If substrate remain, we have to find \mathrm{\frac{A}{A_{0}}}

\mathrm{\therefore } A/c to rate law equation
     \mathrm{-k t=\ln \left(A / A_{0}\right) }
   \mathrm{A / A_{0}=e^{-k t}=e^{-0.0231 \times 2 \times 60}}
\mathrm{A / A_{0}=0.0625} 

Hence \mathrm{6.25\%} reactant will be left after 2 hour.

Posted by

avinash.dongre

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