EAMCET Medical EAMCET Medical Solved Paper-2003

  • question_answer
    The rate constant of a reaction at temperature 200 K is 10 times less than the rate constant at 400 K. What is the activation energy \[{{E}_{a}}\] of the reaction? (R = Gas constant)

    A)  1842.4 R             

    B)  921.27 R

    C)  460.6 R                

    D)  230.3 R

    Correct Answer: B

    Solution :

                     Activation energy can be calculated with the help of Arrhenius equation. \[\log \frac{{{K}_{2}}}{{{K}_{1}}}=\frac{{{E}_{a}}}{2.303R}\left[ \frac{{{T}_{2}}-{{T}_{1}}}{{{T}_{1}}{{T}_{2}}} \right]\] Where, \[{{K}_{1}}=\]Rate constant at \[{{T}_{1}}\]temperature \[{{K}_{2}}=\]Rate constant at \[{{T}_{2}}\] temperature \[{{E}_{a}}=\]Activation Energy                   R = Gas constant                         \[{{T}_{1}},{{T}_{2}}=\]Temperature in Kelvin             \[\log \frac{10}{1}=\frac{{{E}_{a}}}{2.303R}\left[ \frac{400-200}{400\times 200} \right]\] \[1=\frac{{{E}_{a}}}{2.303R}\left[ \frac{200}{400\times 200} \right]\] \[{{E}_{a}}=2.303\times R\times 400\] \[{{E}_{a}}=921.2R\]


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