Uttarakhand PMT Uttarakhand PMT Solved Paper-2009

  • question_answer
    The rate of a gaseous reaction triples when temperature is increased by\[10{}^\circ C\]from\[25{}^\circ C\]. The energy of activation of the reaction (in kJ \[mo{{l}^{-1}}\]) will be

    A)  40            

    B)  70

    C)  83.8           

    D)  200

    Correct Answer: C

    Solution :

     Given, \[{{\text{T}}_{1}}=25{}^\circ C=25+273=298\text{ }K\] \[{{T}_{2}}=(25+10{}^\circ C)=35{}^\circ C=308\text{ }K\] Rate\[\propto k\] \[\Rightarrow \] \[\frac{{{(Rate)}_{25{}^\circ }}}{{{(Rate)}_{35{}^\circ }}}=\frac{{{k}_{25{}^\circ }}}{{{k}_{35{}^\circ }}}\] \[\frac{{{k}_{25{}^\circ }}}{{{k}_{35{}^\circ }}}=\frac{1}{3}\] From Arrhenius equation, \[\log \frac{{{k}_{25{}^\circ }}}{{{k}_{35{}^\circ }}}=\frac{{{E}_{a}}}{2.303R}\left[ \frac{1}{{{T}_{1}}}-\frac{1}{{{T}_{2}}} \right]\] \[\log 3=\frac{{{E}_{a}}}{2.30\times 8.314\times {{10}^{-3}}}\left[ \frac{1}{298}-\frac{1}{308} \right]\] \[0.477=\frac{{{E}_{a}}}{2.30\times 8.314\times {{10}^{-3}}}\left[ \frac{10}{298\times 308} \right]\] \[\therefore \] \[{{E}_{a}}=83.8\,kJ\,mo{{l}^{-1}}\]


You need to login to perform this action.
You will be redirected in 3 sec spinner