Question

Factors responsible for base strength comparison of amines in aqueous solution ?
A.Availability of lone pair on nitrogen
B.Lone pair donating power of nitrogen
C.Stability of conjugate acid formed by solvation through H-bonding
D.All of the above

Answer 1

Hint: In general language the compound having ability to donate lone pair to $\mathop H\nolimits^ + $ ions is known as base . The basic strength of a base is decided by how easily it can donate electrons and how stable its conjugate acid is

Complete step by step answer:
Amines have nitrogen as its central atom which contains a lone pair of electrons . The basic strength of a base is decided by how easily it can donate lone pair and since nitrogen in amines has a lone pair in its s orbital and completely filled p orbital therefore nitrogen’s electron donating power is an important factor for comparison of basic strength .
Any compound reacts because it wants to be stabilized so when amines will take part in a reaction then the rate of reaction will depend upon how stable its conjugate acid is . More stable the conjugate acid the more will be the rate of reaction and hence the more is basic strength .

So, the correct answer is Option D .

Note:
As we know that basic strength is determined by availability of lone pairs so when a lone pair is in conjugation then sharing this lone pair will make compound unstable because conjugation increases stability of compound . So we should take care that when a lone pair is in conjugation then its basic strength will decrease and if the lone pair of nitrogen is part of an aromatic ring then it will be least basic as aromatic compounds are most stable i.e. least reactive .