Here's why:
* Intermolecular forces: Volatile compounds have weaker intermolecular forces (like Van der Waals forces) compared to non-volatile compounds. These forces are responsible for holding molecules together in a liquid state. Weaker forces mean less energy is required to overcome them and break the molecules apart, leading to lower boiling points.
* Molecular weight: Volatile compounds often have lower molecular weights. Smaller molecules have weaker intermolecular forces, again leading to lower boiling points.
Examples of volatile compounds and their boiling points:
* Diethyl ether: Boiling point: 34.6 °C
* Acetone: Boiling point: 56.05 °C
* Methanol: Boiling point: 64.7 °C
* Ethanol: Boiling point: 78.37 °C
It's important to note that:
* The boiling point of a compound depends on various factors, including pressure, and the term "volatile" is relative to the specific application and context.
* Some compounds may be volatile at room temperature, but still have relatively high boiling points. For example, hexane has a boiling point of 69 °C, yet it's still considered volatile due to its high vapor pressure at room temperature.
So, instead of talking about boiling points of volatile compounds, it's more accurate to say that volatile compounds have a tendency to evaporate easily at room temperature due to their weaker intermolecular forces and lower molecular weights.
