Basicity order among drawn amines and heterocycles

14 questions on Basicity order among drawn amines and heterocycles from the General Organic Chemistry II: Acids and Bases chapter: 3 NEET level, 5 JEE Main, 6 JEE Advanced. Each one opens with its answer and solution.

• Four nitrogen compounds are shown beside the options (the drawn compound is ammonia, pKaH 9.3, for reference). Which structure is the strongest base? NEET level, drawn structure
• Four anilines are shown beside the options (the drawn compound is aniline). Which structure is the weakest base? NEET level, drawn structure
• Four nitrogen compounds are shown beside the options (the drawn compound is pyrimidine, for reference). Which structure is the strongest base? NEET level, drawn structure
• The compound shown is an aromatic heterocycle that is an extremely weak base (pKaH about -4). The reason is that JEE Main level, drawn structure
• Four heterocycles are shown beside the options (the drawn compound is thiazole, for reference). Which structure is the strongest base? JEE Main level, drawn structure
• Four compounds are shown beside the options (the drawn compound is urea, for reference). Which structure is the strongest base? JEE Main level, drawn structure
• Four amines are shown beside the options (the drawn compound is aniline, pKaH 4.6). Select ALL the structures that are stronger bases than the drawn compound. JEE Main level, drawn structure
• Four nitrogen compounds are shown beside the options (the drawn compound is ethylamine, for reference). Which structure is the strongest base? JEE Main level, drawn structure
• The compound shown has several nitrogen atoms. Count the nitrogen atoms whose lone pair can accept a proton from dilute acid. Treat as non-basic any nitrogen wh... JEE Advanced level, drawn structure
• The compound shown is protonated by acid. At which nitrogen does protonation occur, and why? JEE Advanced level, drawn structure
• Four tertiary amines are shown beside the options (the drawn compound is piperidine, for reference). Taking pKaH in water, which structure is the strongest base... JEE Advanced level, drawn structure
• Four heterocycles are shown beside the options (the drawn compound is pyridine, pKaH 5.2). Select ALL the structures that are stronger bases than the drawn comp... JEE Advanced level, drawn structure
• The compound shown is an amide. Select ALL the correct statements about its protonation. JEE Advanced level, drawn structure
• Four cyclic secondary amines are shown beside the options (the drawn compound is piperazine, for reference). Taking pKaH in water, which structure is the SECOND... JEE Advanced level, drawn structure