JEE Main & Advanced JEE Main Paper (Held On 12-Jan-2019 Morning)

  • question_answer
    The correct order for acid strength of compounds \[CH\equiv CH,C{{H}_{3}}-C\equiv CH\] and \[C{{H}_{2}}=C{{H}_{2}}\]is as follows [JEE Main Online Paper Held On 12-Jan-2019 Morning]

    A) \[C{{H}_{3}}-C\equiv CH>CH\equiv CH>C{{H}_{2}}=C{{H}_{2}}\]

    B) \[C{{H}_{3}}-C\equiv CH>C{{H}_{2}}=C{{H}_{2}}>HC\equiv CH\]

    C) \[HC\equiv CH>C{{H}_{3}}-C\equiv CH>C{{H}_{2}}=C{{H}_{2}}\]

    D) \[CH\equiv CH>C{{H}_{2}}=C{{H}_{2}}>C{{H}_{3}}-C\equiv CH\]

    Correct Answer: C

    Solution :

    As the s-character of \[CH\text{ }bond\] increases, acidity increases. Thus, acidity order \[\underset{\begin{smallmatrix}  sP \\  (50%) \end{smallmatrix}}{\mathop{CH\equiv CH>}}\,\underset{\begin{smallmatrix}  s{{P}^{2}} \\  (33.3%) \end{smallmatrix}}{\mathop{C{{H}_{2}}=C{{H}_{2}}}}\,\] +1 effect (\[-C{{H}_{3}}\]group) reduces acidity Thus, acidity order well be \[CH\equiv CH>C{{H}_{3}}-C\equiv CH>C{{H}_{2}}=C{{H}_{2}}\]


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