Which of the following orders is correct regarding basicity of indicated molecules?

Which of the following orders is correct regarding basicity of indicated molecules?
  1. $N, N$-Dimethyltoluidine $>p$-toluidine $>$ aniline $>p$-nitroaniline
  2. Aniline $>N, N$-dimethyl- $p$-toluidine $>p$-toluidine $>$ aniline
  3. $p$-Toluidine $>N, N$-dimethyl $-p$-toluidine $>$ aniline $>p$-nitroaniline
  4. $N, N$-Dimethyltoluidine $>$ aniline $>p$-toluidine $>p$-nitroaniline

Solution

Aniline is a weaker base. It is a Lewis base, i.e. the lone pair present on nitrogen can be given to the Lewis acids. The electron-releasing group present at the para position increases the electron density on nitrogen and thus makes it more basic. For example, para-toluidine is more basic than aniline. On the other hand, the presence of electron-withdrawing group decreases the electron density on nitrogen and hence makes it less basic. For example, $p$-nitroaniline is less basic than aniline. .

Asked in: JEE-TOPICTESTS-CHEMISTRY

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