Question

Question: Rank the compounds in each group in order of increasing basicity.

a.

b.

Short answer

Answer

a.

b.

Step-by-step solution

Basicity of arylamines and alkylamines

Arylamines contain a benzene group with the amine functional group. Alkylamines contain an alkyl group with the amine functional group.

Arylamines are less basic than alkylamines because the electron pair on N is delocalized in arylamines.

Effect of substituents on arylamines

• Electron-donor groups add electron density to the benzene ring, making arylamine more basic than aniline.

• Electron-withdrawing groups remove electron density from the benzene ring, making arylamine less basic than aniline.

Explanation

a. Aniline with the methoxy substituent at the para position increases the electron density in the ring, making the compound more basic than aniline.

Aniline with the ester substituent at the para position decreases the electron density of the ring, making the compound less basic than aniline.

Therefore, the increasing order of basicity is as shown.

Increasing basicity order for a

b. Aniline with the nitro group substituent at the para position has lower electron density in the ring. Thus, the compound becomes less basic than aniline. Arylamine (aniline) is lesser basic than cyclohexylamine.

Therefore, the increasing order of basicity is as shown.

Increasing basicity order for b