JCECE Engineering JCECE Engineering Solved Paper-2010

  • question_answer
    In aqueous solutions, the basic strength of amines decreases in the order

    A) \[C{{H}_{3}}N{{H}_{2}}>{{(C{{H}_{3}})}_{2}}N{{H}_{2}}>{{(C{{H}_{3}})}_{3}}N\]

    B) \[{{(C{{H}_{3}})}_{2}}NH>{{(C{{H}_{3}})}_{3}}N>C{{H}_{3}}N{{H}_{2}}\]

    C) \[{{(C{{H}_{3}})}_{3}}N>{{(C{{H}_{3}})}_{2}}NH>C{{H}_{3}}N{{H}_{2}}\]

    D)  \[{{(C{{H}_{3}})}_{2}}NH>C{{H}_{3}}N{{H}_{2}}>{{(C{{H}_{3}})}_{3}}N\]

    Correct Answer: D

    Solution :

    Basicity of amines depends upon the availability of lone pair of electrons of nitrogen for donation. Electron releasing group increases the electron density over nitrogen, thus increases the basic character. \[{{3}^{o}}\] methyl amine although contains three electron releasing groups but is least basic because of steric hindrance. Hence, the order of basic character is                 \[{{(C{{H}_{3}})}_{2}}NH>C{{H}_{3}}N{{H}_{2}}>{{(C{{H}_{3}})}_{3}}N\]


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