Why aniline is less basic than ammonia?

Answer 1

Alkyl groups are slightly electron donating.  The methyl groups on the amine in N,N dimethylaniline contribute electron density to the nitrogen lone pair, making it more likely to reach out and grab a proton (ie more basic).

Answer 2

Due to presence of conjugated (alternated) double bonds, and thus alternated pi bonds of benzene ring, the lone pair can indulge in resonance stabilization, thus delocalizing

the lone pair loses its intensity at the basic centre (nitrogen). This can be thought of as though the lone pair goes around in the benzene ring, thus spending less time cooped up near nitrogen.

For cyclohexyl

amide, there are no pi bonds and thus the lone pair of nitrogen stays at the basic centre.

One should understand that for a compound to be more basic, the lone pair should be localized, which is not the case for aniline. Thus we can explain why aniline is less basic than cyclohexyl

amide...

Answer 3

In cyclohexylamine, the electron donating group is attached to sp3 hybridized cyclohexane ring while in case of aniline it is attached with sp2 hybridized carbon containing benzene ring.

Due, to more s -character in benzene ring, here becomes the de localization of π-electrons in the ring and further the NH2 -group donates more electron to the ring so that it reduces the +ve charge centers and stabilizes the ring and makes it less acidic means the basicity increases.

While , in case of cyclohexylamine, the lone pair of electron donating NH2 -group is not de localized over cyclohexane ring and is available for donation, which makes the compound more basic than aniline.

Answer 4

In case of Aniline the electron pair of nitrogen becomes involved in resonance with aromatic ring and is not available for proton.

Answer 5

Aniline is less basic than methylamine due to the arene ring capacity at delocalising the lone pair of electrons present on the nitrogen.

Answer 6

Since tha pka of the aniline ion is equal to 4.6, the anilinium ion is a stronger acid than the methylaminium ion, and aniline (c6h5nh2) is a weaker base than methylamine (ch3nh2).