KVPY Sample Paper KVPY Stream-SX Model Paper-6

  • question_answer
    Consider the following reactions in which all the reactants and the products are in gaseous state
    \[2PQ{{P}_{2}}+{{Q}_{2}};{{K}_{1}}=2.5\times {{10}^{5}}\]
    \[PQ+1/2{{R}_{2}}PQR;{{K}_{2}}=5\times {{10}^{-3}}\]
    The value of \[{{K}_{3}}\] for the equilibrium \[\frac{1}{2}{{P}_{2}}+\frac{1}{2}{{Q}_{2}}+\frac{1}{2}{{R}_{2}}PQR,\] is

    A) \[2.5\times {{10}^{-3}}\]                     

    B) \[2.5\times {{10}^{3}}\]

    C) \[1.0\times {{10}^{-5}}\]                     

    D) \[5\times {{10}^{3}}\]

    Correct Answer: C

    Solution :

    Given, \[2PQ{{P}_{2}}+{{Q}_{2}};\]
    \[{{K}_{1}}=\frac{[{{P}_{2}}][{{Q}_{2}}]}{{{[PQ]}^{2}}}=2.5\times {{10}^{5}}\]
    \[\operatorname{PQ}+\frac{1}{2}{{R}_{2}}PQR;\]
    \[{{\operatorname{K}}_{2}}=\frac{[PQR]}{[PQ]{{[{{R}_{2}}]}^{1/2}}}=5\times 1{{0}^{-3}}\]
    Required equilibrium is: \[1/2{{P}_{2}}+1/2{{Q}_{2}}+1/2{{R}_{2}}PQR;\]
    \[{{K}_{3}}=\frac{[PQR]}{{{[{{P}_{2}}]}^{1/2}}{{[{{Q}_{2}}]}^{1/2}}{{[{{R}_{2}}]}^{1/2}}}\]
    or         \[{{K}_{3}}={{K}_{2}}\times \sqrt{\frac{1}{{{K}_{1}}}}\]
    \[=5\times {{10}^{-3}}\times \sqrt{\frac{1}{2.5\times {{10}^{5}}}}=\frac{5\times {{10}^{-3}}}{0.5\times {{10}^{3}}}=1\times {{10}^{-5}}\]


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