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CUET · CHEMISTRY · PYQ PAPER 2023

Amines are reactive in nature, mainly due to difference in electronegativity between Nitrogen and Hydrogen and, due to lone pair of electrons on Nitrogen. Amines behave like nucleophiles and as good lewis bases and there are various reactions to support this. Different degree of amines differ in their reactivity due to steric hinderance and electronic effects. Aromatic amines are less basic due to + R effect, hence have higher pkb value than aliphatic amines. Basic strength of amines also depends on stability of corresponding conjugate acid in aqueous medium.
Which of the following will be having lowest \(p K_b\) in gaseous medium?

  1. A N,N-Diethylethanamine
  2. B sec-Butylamine
  3. C Diethylamine
  4. D Ethylamine
Verified Solution

Answer & Solution

Correct Answer

(A) N,N-Diethylethanamine

Step-by-step Solution

Detailed explanation

Tertiary amines are most basic in gaseous medium due to +I effect of three alkyl groups stabilizing the conjugate acid. N,N-Diethylethanamine (Triethylamine) is a tertiary amine. Lowest \(pK_b\) corresponds to the most basic amine. N,N-Diethylethanamine