Question

The order of basicity of amines in gaseous state is:

• A. \($1^0 > 2^0 > 3^0 > NH_3$\)
• B. \($3^0 > 2^0 > NH_3 > 1^?$\)
• C. \($3^0 > 2^0 > 1^0 > NH_3$\)
• D. \($NH_3 > 1^0 > 2^0 > 3^0$\)

Answer 1

The Correct Option is C

The basicity of amines in the gaseous state can be understood through their ability to donate a pair of electrons. The stronger the basicity, the more readily the compound can donate electrons. In amines, the lone pair on the nitrogen atom is responsible for the basic nature of these compounds.

1. Basicity and Alkyl Groups: The introduction of alkyl groups increases the electron density on nitrogen through the +I (inductive) effect, making the lone pair more available for donation. This increases the basicity. 
2. Primary, Secondary, and Tertiary Amines:
   • Tertiary Amine (\(3^0\)): Has three alkyl groups, which maximizes the electron-releasing effect, thus making tertiary amines the most basic in the gaseous state.
   • Secondary Amine (\(2^0\)): Has two alkyl groups, making it less basic than tertiary amines but more basic than primary amines.
   • Primary Amine (\(1^0\)): Has one alkyl group, making it less basic than both secondary and tertiary amines.
   • Ammonia (\(NH_3\)): Lacks alkyl groups and relies only on the lone pair for its basic character, making it the least basic.
3. Conclusion: The order of basicity of amines in the gaseous state is determined by the number of alkyl groups present, which enhance the basicity through the inductive effect.

Therefore, the correct order of basicity of amines in the gaseous state is:

\(3^0 > 2^0 > 1^0 > NH_3\), which matches the correct answer option.