Question

Which is the stronger base in each pair?a. Ammonia or ethylamineb.Triethylamine or pyridine

Accepted Answer

Step 1: Understand the concept of base strength. A stronger base has a greater ability to accept protons (H⁺). In organic chemistry, the strength of a base is influenced by the availability of the lone pair of electrons on the nitrogen atom and the surrounding molecular structure. Step 2: Analyze part (a): Ammonia (NH₃) vs. Ethylamine (CH₃CH₂NH₂). Ethylamine is an amine with an ethyl group attached to the nitrogen. The ethyl group is an electron-donating group, which increases the electron density on the nitrogen atom, making it more available to accept a proton. Ammonia lacks such an electron-donating group, so its nitrogen is less nucleophilic. Step 3: Conclude for part (a): Ethylamine is the stronger base compared to ammonia because the electron-donating ethyl group enhances the basicity of the nitrogen atom. Step 4: Analyze part (b): Triethylamine ((CH₃CH₂)₃N) vs. Pyridine (C₅H₅N). Triethylamine has three ethyl groups attached to the nitrogen, which significantly increase the electron density on the nitrogen, enhancing its basicity. Pyridine, on the other hand, is an aromatic compound where the lone pair of electrons on the nitrogen is delocalized into the aromatic ring, reducing its availability to accept a proton. Step 5: Conclude for part (b): Triethylamine is the stronger base compared to pyridine because the lone pair on the nitrogen in triethylamine is more available for protonation, while in pyridine, the lone pair is partially delocalized into the aromatic system.

Which is the stronger base in each pair?
a. Ammonia or ethylamine
b.Triethylamine or pyridine

비슷한 문제에 대한 검증된 영상 답변:

주요 개념

Basicity

Amine Structure

Resonance and Electron Delocalization