DUMET Medical DUMET Medical Solved Paper-2010

  • question_answer
    The first-order reaction, \[2{{N}_{2}}O(g)\to 2{{N}_{2}}(g)+{{O}_{2}}(g)\] has a rate constant of \[1.3\times {{10}^{-11}}{{s}^{-1}}\] at \[{{270}^{o}}C\]and \[4.5\times {{10}^{-10}}{{s}^{-1}}\]at\[{{350}^{o}}C\]. What is the activation energy for this reaction?

    A)  15kJ  

    B)  30kJ  

    C)  68 kJ  

    D)  120 kJ

    Correct Answer: D

    Solution :

    From Arrhenius equation, \[\log \frac{{{k}_{2}}}{{{k}_{1}}}=\frac{{{E}_{a}}}{2.303R}\left[ \frac{1}{{{T}_{1}}}-\frac{1}{{{T}_{2}}} \right]\] \[\log \frac{4.5\times {{10}^{-10}}}{1.3\times {{10}^{-11}}}=\frac{{{E}_{a}}}{2.303\times 8.314}\] \[\left[ \frac{1}{(270+273)}-\frac{1}{(350+273)} \right]\] \[\log \,\,34.62=\frac{{{E}_{a}}}{2.303\times 8.314}\left[ \frac{1}{543}-\frac{1}{623} \right]\] \[1.539=\frac{{{E}_{a}}}{2.303\times 8.314}\left[ \frac{80}{543\times 623} \right]\] \[{{E}_{a}}=\frac{1.539\times 2.303\times 8.314\times 543\times 623}{80}\] \[=\frac{9.968\times {{10}^{6}}}{80}\] \[=1.246\times {{10}^{5}}J=124\,kJ\approx 120\,kJ\]


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