CMC Medical CMC-Medical VELLORE Solved Paper-2012

  • question_answer
    The rate of a first order reaction is \[1.5\times {{10}^{-2}}\]\[mol\,{{L}^{-}}\,{{\min }^{-1}}\] at 0.5 M concentration of the reactant. The half-life of the reaction is

    A)  0.383 min           

    B)  23.1 min

    C)  8.73 min             

    D)  7.53 min

    Correct Answer: B

    Solution :

                    For the first order reaction \[\text{Rate}\left( \frac{dx}{dt} \right)=k[A]\] \[[A]\to \] concentration of reactant \[k\to \]rate constant Given that \[\frac{dx}{dt}=1.5\times {{10}^{-2}}mol\,{{L}^{-1}}\,{{\min }^{-1}}\] \[k=?\]and \[[A]=0.5\,M\] \[\therefore \]  \[1.5\times {{10}^{-2}}=k\times 0.5\] \[\therefore \]  \[k=\frac{1.5\times {{10}^{-2}}}{0.5}=3\times {{10}^{-2}}{{\min }^{-1}}\] For first order reaction, Half-life period, \[{{t}_{1/2}}=\frac{0.693}{k}=\frac{0.693}{3\times {{10}^{-2}}}\]       \[=23.1\text{ }min\]


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