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NEET Sample Paper NEET Sample Test Paper-42

  • question_answer
    75% of the first order reaction was completed in 32 min. 50% of the reaction was completed in:

    A) 24 min                         

    B) 8min  

    C) 16 min             

    D) 4min

    Correct Answer: C

    Solution :

    For the 1st order reaction \[\operatorname{k}=\frac{2.303}{t}\,\,\,log\frac{a}{a-x}\] \[\operatorname{when}\,\,=\frac{75a}{100}=0.75a\] \[\operatorname{k}=\frac{2.303}{32}\,\,\,log\frac{a}{a-0.75a}\] \[\frac{2.303}{32}\,\,\,log\frac{a}{0.25}\] \[\operatorname{t}\,\,in\,\,50%=\frac{2.303}{k}log\,\frac{100}{50}\] \[=\frac{2.303}{2.303}32\,\frac{log\,2}{log\,4}=16min\].


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