NEET AIPMT SOLVED PAPER SCREENING 2007

  • question_answer
                    In a first order reaction \[A\xrightarrow[{}]{{}}B\], if k is rate constant and  initial  concentration  of the reactant A is 0.5 M then the half-life is:                                                                                                                                   

    A)                 \[\frac{0.693}{0.5\,k}\] 

    B)                 \[\frac{\log \,2}{k}\]      

    C)                 \[\frac{\log \,2}{k\sqrt{0.5}}\]   

    D)                 \[\frac{\ln \,2}{k}\]

    Correct Answer: D

    Solution :

                    For first order reaction                 \[k=\frac{2.303}{t}\log \frac{a}{(a-x)}\]                 \[{{t}_{1/2}}=\frac{2.303}{k}\log \frac{a}{a-\frac{a}{2}}\]                 \[=\frac{2.303}{k}\log \,2\] \[or\frac{\ln \,2}{k}\]


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