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DUMET Medical DUMET Medical Solved Paper-2010

  • question_answer
    The free energy of formation of NO is 78 kJ \[mo{{l}^{-1}}\] at the temperature of an automobile engine (1000 K). What is the equilibrium constant for this reaction at 1000 K? \[\frac{1}{2}{{N}_{2}}(g)+\frac{1}{2}{{O}_{2}}(g)NO(g)\]

    A)  \[8.4\times {{10}^{-5}}\]        

    B)  \[7.1\times {{10}^{-9}}\]

    C)  \[4.2\times {{10}^{-10}}\]

    D)  \[1.7\times {{10}^{-19}}\]

    Correct Answer: A

    Solution :

    Free energy and equilibrium constant are related as, \[\Delta \,G=-2.303\,\,RT\,\log \,K\] \[78\times {{10}^{3}}=-2.303\times 8.314\times 1000\times \log \,\,K\] \[\log K=-\frac{78}{2.303\times 8.314}\] \[=-4.073\] K = antilog \[(-4.0.73)\] \[=8.43\times {{10}^{-5}}\]


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