Which of the following amines is the weakest base?Select answer from the options belowanilinep-nitroanilinem-methylanilinep-ethylaniline

The weakest base among the options provided is p-nitroaniline.

Here's why:

1. Aniline is a weak base due to the delocalization of the lone pair of nitrogen into the benzene ring, which makes it less available for protonation.

2. p-nitroaniline is even weaker than aniline because the nitro group at the para position is a strong -I (inductive effect) and -R (resonance effect) group. This means it pulls the electron density towards itself, further reducing the availability of the lone pair on nitrogen for protonation.

3. m-methylaniline and p-ethylaniline are stronger bases than aniline because the methyl and ethyl groups are +I effect groups, meaning they push the electron density towards the nitrogen, making the lone pair more available for protonation.

So, the order of basicity is: p-nitroaniline < aniline < m-methylaniline < p-ethylaniline. Therefore, p-nitroaniline is the weakest base among the given options.