Q5 / 155 · WBJEE 2016 · Chemistry

The correct order of basicity of the following compounds is Figure

  • A
    $1 < 2 < 3 < 4$
  • B
    $1 < 2 < 4 < 3$
  • Correct answer
    C
    $2 < 1 < 3 < 4$
  • D
    $4 < 3 < 2 < 1$

Solution

The correct order is $2 < 1 < 3 < 4$. Since, more the number of $2^{\circ}$ - NH- group, more is the basic nature. (1) Thus, 3 and 4 are more basic than 1 and 2 . (ii) Between 3 and 4,4 has one two - $\mathrm{NH}_{2}$ group while 3 has only one $-\mathrm{NH}_{2}$ group. $\therefore 4$ is more basic than 3 (iii) Between 1 and 2,1 has one $-\mathrm{NH}_{2}$ group with no resonance, thus is more basic than 2.

Hence, the correct answer is option: 'C'.

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