Question

The correct order of basic nature is given in:

• A.
• B.
• C. $C{H}_3-N{H}_2<C{H}_3-NH-C{H}_3<{\left(C{H}_3\right)}_{3}N$ (in non − polar medium)
• D. ${\left(C{H}_3\right)}_{2}NH>C{H}_{3}N{H}_2>{\left(C{H}_3\right)}_{3}N$ (in polar medium)

Answer 1

Answer: (A), (B), (C), (D)

The correct options are
A
B
C $C{H}_3-N{H}_2<C{H}_3-NH-C{H}_3<{\left(C{H}_3\right)}_{3}N$ (in non − polar medium)
D ${\left(C{H}_3\right)}_{2}NH>C{H}_{3}N{H}_2>{\left(C{H}_3\right)}_{3}N$ (in polar medium)

(a) Pyridine is more basic than aniline due to availibity of lone pair of electron. Due to ortho effect, o-nitroaniline is the weakest base amongst them.

(b) Pyridine is most basic due to availibility of lone pair to donate. Aniline is less basic than pyridine since the lone pair is delocalised inside the ring which makes it less available to donate. Pyrrole is least basic as lone pair is involved in aromaticity and no longer available.

(c) In non polar medium +I effect is more pronounced.

(d) In polar medium, basicity is decided by inductive effect, solvation effect and steric factor.