NEET Chemistry NEET PYQ-Chemical Kinetics

  • question_answer
    The rate constants \[{{k}_{1}}\] and \[{{k}_{2}}\] for two different reactions are \[{{10}^{16}}.{{e}^{-2000/T}}\] and \[{{10}^{15}}.{{e}^{-1000/T}},\] respectively. The temperature at which \[{{k}_{1}}={{k}_{2}}\] is [AIPMT (S) 2008]

    A) 1000 K

    B) \[\frac{2000}{2.303}K\]

    C) 2000K

    D) \[\frac{1000}{2.303}K\]

    Correct Answer: D

    Solution :

    [d] Key Idea: The Arrhenius equation is represented as\[k=A{{e}^{-{{E}_{a}}/RT}}\]
    In the given equations, first take log and. Then compare them.
    \[{{k}_{1}}={{10}^{16}}{{e}^{-2000/T}}\]
    \[{{k}_{2}}={{10}^{15}}{{e}^{-1000/T}}\]On taking log, we get
    \[\log {{k}_{1}}=\log {{10}^{16}}-\frac{2000}{2.303T}\]                      …(i)
    \[\log {{k}_{2}}=\log {{10}^{15}}-\frac{1000}{2.303T}\]                      …(ii)
    \[\because \]\[{{k}_{1}}={{k}_{2}}\]Hence, from Eqs. (i) and (ii) \[T=\frac{1000}{2.303}K\]


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