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Manipal Engineering Manipal Engineering Solved Paper-2011

  • question_answer
    The rate constant for the first order reaction is\[60{{s}^{-1}}\]. How much time will it take to reduce the concentration of the reactant to\[\frac{1}{16}th\]value?

    A) \[4.6\times {{10}^{-2}}s\]

    B)                        \[4.6\times {{10}^{4}}s\]

    C)                        \[4.6\times {{10}^{2}}s\]

    D)                        \[4.6\times {{10}^{-4}}s\]

    Correct Answer: A

    Solution :

    \[t=\frac{2.303}{k}\log \frac{{{[A]}_{0}}}{[A]}\]   \[=\frac{2.303}{60}=\log \frac{a}{\frac{a}{16}}=\frac{2.303}{60}\log 16\]    \[=\frac{2.303}{60}\times 1.204\]    \[=0.0462s=4.6\times {{10}^{-2}}s\]


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