Question

The increasing basicity order of the following compounds in the gas phase is:

• A. $A<B<D<C$
• B. $D<A<B<C$
• C. $D<C<B<A$
• D. $A<B<C<D$

Answer 1

The correct option is B $D<A<B<C$

$+I$ effect increases the basic character of amines in the gaseous phase.
Since tertiary amine (C) has more $+I$ effect, it is the most basic followed by secondary (B) and primary (A).
Due to the resonance of lone pairs into the benzene ring, aromatic amines are weaker than aliphatic amines.
Hence, the correct decreasing order is: $D<A<B<C$