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

## ${C}_{2} {H}_{8} O$

Dec 6, 2016

The most obvious one in $\text{hydrogen bonding}$.

#### 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 $\text{1-propanol}$ has a normal boiling point of $97 - 98$ ""^@C. And we compare this to that of $\text{isopropanol}$, $82.6$ ""^@C, and $\text{ethanol}$, $78.0$ ""^@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 $\text{n-butanol,}$ $117.7$ ""^@C, and $\text{n-pentanol,}$ $137 - 139$ ""^@C.