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WB JEE Medical WB JEE Medical Solved Paper-2008

  • question_answer
    Which one of the following pairs gives effervescence with aq. \[\text{NaHC}{{\text{O}}_{\text{3}}}\]? \[\underset{(II)}{\mathop{\underset{C{{H}_{3}}COOC{{H}_{3}}}{\mathop{\underset{(I)}{\mathop{C{{H}_{3}}COCl}}\,}}\,}}\,\] \[\underset{(IV)}{\mathop{\underset{C{{H}_{3}}COOCOC{{H}_{3}}}{\mathop{\underset{(II)}{\mathop{C{{H}_{3}}COC{{H}_{3}}}}\,}}\,}}\,\]

    A)  I and II                

    B)  I and IV

    C)  II and III              

    D)  I and III

    Correct Answer: B

    Solution :

                     Due to strong negative inductive effect shown by ?Cl and \[-OCOC{{H}_{3}}\]group, acid chloride and acid anhydride are highly reactive among acid derivatives. They react independently with water even in the absence of catalyst to give carboxylic acid. \[C{{H}_{3}}-\overset{O}{\mathop{\overset{|\,\,|}{\mathop{C}}\,}}\,-Cl\xrightarrow{NaHC{{O}_{3}}(aq)}C{{H}_{3}}-\overset{O}{\mathop{\overset{|\,\,|}{\mathop{C}}\,}}\,-ONa\] \[+C{{O}_{2}}+HCl\]                 \[C{{H}_{3}}\overset{O}{\mathop{\overset{||}{\mathop{C}}\,}}\,-O-\overset{O}{\mathop{\overset{||}{\mathop{C}}\,}}\,C{{H}_{3}}\xrightarrow{NaHC{{O}_{3}}(aq)}\]\[2C{{H}_{3}}-\overset{O}{\mathop{\overset{|\,\,|}{\mathop{C}}\,}}\,-ONa+C{{O}_{2}}\]


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