MGIMS WARDHA MGIMS WARDHA Solved Paper-2011

  • question_answer
    For a first order reaction at\[27{}^\circ C,\]the ratio of time required for 75% completion to 25% completion of reaction is

    A)  \[\log \frac{4}{3}\]                         

    B)  \[\log \frac{3}{4}\]

    C)  \[\frac{\log \,4}{\log 4/3}\]                        

    D)  \[\frac{\log \,4/3}{\log 4}\]

    Correct Answer: C

    Solution :

                     For a first order reaction, \[t=\frac{2.303}{k}{{\log }_{10}}\frac{a}{a-x}\] Let initial amount of reactant is 100. \[\frac{{{t}_{1}}}{{{t}_{2}}}=\frac{\log \frac{100}{100-75}}{\log \frac{100}{100-25}}\] [k remains constant] \[=\frac{\log \frac{100}{25}}{\log \frac{100}{75}}=\frac{\log 4}{\log 4/3}\]


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