The increasing order of pK_b values of the fo | vedclass

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(A) The basicity of amines is inversely proportional to their $pK_b$ values. Stronger bases have lower $pK_b$ values.$I$: $p$-methoxyn,$N,N$-dimethyla

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$I < II < IV < III$

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(A) The basicity of amines is inversely proportional to their $pK_b$ values. Stronger bases have lower $pK_b$ values.$I$: $p$-methoxyn,$N,N$-dimethylaniline. The $-OCH_3$ group is electron-donating ($+M$ effect),which increases the electron density on the nitrogen atom,making it the strongest base.$II$: $N,N$-dimethylaniline. It is more basic than aniline due to the $+I$ effect of two methyl groups.$IV$: $m$-hydroxy-$N$-methylaniline. The $-OH$ group has a $-I$ effect (electron-withdrawing) at the meta position,decreasing basicity compared to $II$.$III$: $m$-cyano-$N$-methylaniline. The $-CN$ group is a strong electron-withdrawing group ($-I$ and $-M$ effects),which significantly decreases the basicity,making it the weakest base.Therefore,the order of basicity is $I > II > IV > III$.Since $pK_b$ is inversely proportional to basicity,the increasing order of $pK_b$ values is $I < II < IV < III$.

The increasing order of $pK_b$ values of the following compounds is

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