The preferred sits of protonation in the following compounds are

The preferred sites of protonation in the following compounds are

The preferred sites of protonation in the following compounds are:

The correct order of acidic nature of protons in the following compound is

The correct order of acidic nature of protons in the following compound is

On mono protonation which nitrogen of the following compound can be protonated.

The most acidic proton and the strongest, nucleophilic nitrogen in the following compound respectively, are