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JEE Main levelSingle correct optionDifficulty 2 of 3nc115

Which is the correct order of basic strength in water of , 4-methylaniline, 4-methoxyaniline and 4-nitroaniline?

  1. A4-methylaniline > 4-methoxyaniline > aniline > 4-nitroaniline
  2. B4-methoxyaniline > 4-methylaniline > aniline > 4-nitroaniline
  3. C4-nitroaniline > aniline > 4-methylaniline > 4-methoxyaniline
  4. Daniline > 4-methoxyaniline > 4-methylaniline > 4-nitroaniline

Answer: B

Electron-donating groups at the para position raise the electron density on nitrogen, and the +R effect of OCH3 (pKa of conjugate acid about 5.3) is larger than the +I/hyperconjugation effect of CH3 (about 5.1). Aniline (4.6) is next, and the strongly withdrawing NO2 (about 1.0) gives the weakest base.
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