Question

What intermolecular forces are present in `C_2H_8O` (1-Propanol)?

`C_2H_8O`

Answer 1

The most obvious one in `"hydrogen bonding"`.

Explanation:

One of the best indicators of intermolecular interaction is the normal boiling point. Molecules with significant intermolecular interaction tend to have higher boiling points. Water, a small molecule, has an exceptionally high boiling point because of intermolecular hydrogen bonding, which persists BETWEEN molecules:

`H-O^(delta-)-H^(delta+)cdotsO^(delta-)-H^(delta+)""_2`

Now `"1-propanol"` has a normal boiling point of `97-98` `""^@C`. And we compare this to that of `"isopropanol"`, `82.6` `""^@C`, and `"ethanol"`, `78.0` `""^@C.`

Given these data, there is another contributor to intermolecular interaction, and here it is the non-polar interaction between hydrocarbyl chains. The longer the chain, the greater the chain-chain interaction, and in long chain alcohols (and alkanes), boiling points will be elevated. Compare the boiling point of `"n-butanol,"` `117.7` `""^@C`, and `"n-pentanol,"` `137-139` `""^@C`.