Question

Draw the structures of (a) ethylamine and (b) trimethylamine. Use dashed lines to show how they would form hydrogen bonds to water molecules.

Accepted Answer

Step 1: Understand the molecular structure of ethylamine (C2H5NH2). Ethylamine consists of an ethyl group (C2H5-) attached to an amine group (-NH2). The nitrogen atom in the amine group has a lone pair of electrons, which makes it capable of forming hydrogen bonds with water molecules. Step 2: Draw the structure of ethylamine. Represent the ethyl group as CH3-CH2- and attach it to the nitrogen atom. The nitrogen atom should have two hydrogen atoms bonded to it and a lone pair of electrons. Step 3: Identify the hydrogen bonding sites for ethylamine. The hydrogen atoms attached to the nitrogen in the -NH2 group can act as hydrogen bond donors, while the lone pair on the nitrogen can act as a hydrogen bond acceptor. Step 4: Draw the structure of trimethylamine (C3H9N). Trimethylamine consists of a nitrogen atom bonded to three methyl groups (CH3-). The nitrogen atom has a lone pair of electrons, which allows it to act as a hydrogen bond acceptor. Step 5: Illustrate the hydrogen bonding interactions with water molecules. For ethylamine, show dashed lines from the hydrogen atoms of the -NH2 group to the oxygen atom of water (hydrogen bond donor) and from the lone pair on nitrogen to a hydrogen atom of water (hydrogen bond acceptor). For trimethylamine, show a dashed line from the lone pair on nitrogen to a hydrogen atom of water (hydrogen bond acceptor).

Draw the structures of (a) ethylamine and (b) trimethylamine. Use dashed lines to show how they would form hydrogen bonds to water molecules.

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Key Concepts

Hydrogen Bonding

Molecular Structure

Polarity