KVPY Sample Paper KVPY Stream-SX Model Paper-13

  • question_answer
    The following results were obtained during kinetic studies of the reaction: \[24+\text{B}\to \text{Products}\]
    Experiment [A] (in mol \[{{\text{L}}^{-1}}\]) [B] (in mol \[{{\text{L}}^{-1}}\]) Initial Rate of Reaction (in mol \[{{\text{L}}^{-1}}\] \[\text{mi}{{\text{n}}^{-1}}\])
    (I) 0.10 0.20 \[6.93\times {{10}^{-3}}\]
    (II) 0.10 0.25 \[6.93\times {{10}^{-3}}\]
    (III) 0.20 0.30 \[1.386\times {{10}^{-2}}\]
    The time in minutest required to consume half of is:

    A) 10

    B) 5

    C) 100

    D) 1

    Correct Answer: B

    Solution :

    \[6.93\times 10{{\,}^{-\,3}}\,=\text{K}\,\times \,{{(0.1)}^{x}}{{(0.2)}^{y}}\]
    \[6.93\times 10{{\,}^{-\,3}}\,=\,\text{K}\,\times \,{{(0.1)}^{x\,}}\,{{(0.25)}^{y}}\]
    So,  \[y=0\]
    and \[1.386\times {{10}^{\,-\,2}}\,=\,\text{K}\,\times \,{{(0.2)}^{x}}\,{{(0.30)}^{y}}\]
                \[\frac{1}{2}\,=\,{{\left( \frac{1}{2} \right)}^{x}}\,x\,=\,1\]
    So,       \[r\,=\,\text{K}\,\times \,(0.1)\,\times \,{{(0.2)}^{0}}\]
    \[6.93\times 10{{\,}^{-\,3}}\,=\,\text{K}\,\times 0.1\,\times \,{{(0.2)}^{0}}\]
                \[\text{K}\,=\,6.93\times {{10}^{-\,2}}\]
    \[{{t}_{\frac{1}{2}}}\,=\,\frac{0.693}{2\text{K}}\,=\,\frac{0.693}{0.69\times {{10}^{\,-\,1}}\times 2}\,=\,\frac{10}{2}\,=\,5.\]


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