Question #fa082

1 Answer
Jan 21, 2015

For ethanol, or #"CH"_3"CH"_2"OH"#, the fact that it has a 2-carbon atom chain doesn't matter when it comes to hydrogen bonding because its ability to form hydrogen bonds comes from its attached functional group called hydroxyl, or #"-OH"#.

Here's how an ethanol molecule looks like

The oxygen atom is shown in red, the carbon atoms in black, and the hydrogen atoms in grey. Notice that you do have a hydrogen atom connected to oxygen, one of the three most electronegative elements; this is what gives the ethanol molecule's ability to form hydrogen bonds with other ethanol molecules.

Much like in the case of water, the hydrogen attached to the oxygen will have a partial positive charge, which implies a partial negative charge for the oxygen atom.

When two ethanol molecules come together, the partial positive hydrogen atom will be attracted by the partial negative oxygen atom, which will result in hydrogen bonding.

As a matter of fact, ethanol is considered to be hygroscopic, i.e. it has the ability to attract and hold water molecules from its surrounding environment. This property is of course based on the fact that it can hydrogen bond with water molecules.