Which of the following compounds has the lowest boiling point?
When it comes to predicting the boiling points of different compounds, several factors come into play. These include molecular weight, intermolecular forces, and the presence of functional groups. In this article, we will explore the various compounds and determine which one has the lowest boiling point among them.
Firstly, it is important to note that molecular weight plays a significant role in determining the boiling point of a compound. Generally, compounds with higher molecular weights tend to have higher boiling points. This is because larger molecules have more electrons, which leads to stronger van der Waals forces of attraction between the molecules. As a result, more energy is required to break these intermolecular forces and convert the compound from a liquid to a gas.
However, molecular weight is not the only factor that influences boiling points. Intermolecular forces also play a crucial role. These forces can be categorized into three types: van der Waals forces, dipole-dipole interactions, and hydrogen bonding. Compounds with stronger intermolecular forces generally have higher boiling points.
Now, let’s examine the compounds in question and determine which one has the lowest boiling point. The compounds are:
1. Methane (CH4)
2. Ethane (C2H6)
3. Ethanol (C2H5OH)
4. Ethanal (CH3CHO)
Among these compounds, methane has the lowest boiling point. This is because methane is a non-polar molecule with only weak van der Waals forces of attraction between its molecules. Ethane, being a larger molecule, has slightly stronger van der Waals forces and, therefore, a higher boiling point than methane.
Ethanol, on the other hand, has a higher boiling point than both methane and ethane due to the presence of hydrogen bonding. Hydrogen bonding occurs when a hydrogen atom is bonded to a highly electronegative atom (such as oxygen or nitrogen) and is attracted to another electronegative atom in a neighboring molecule. This results in stronger intermolecular forces and a higher boiling point.
Ethanal, also known as acetaldehyde, has a higher boiling point than ethanol due to the presence of a carbonyl group (C=O). The carbonyl group can participate in dipole-dipole interactions, which are stronger than van der Waals forces but weaker than hydrogen bonding.
In conclusion, methane has the lowest boiling point among the given compounds. This is due to its non-polar nature and weak van der Waals forces of attraction. Understanding the factors that influence boiling points can help us predict and explain the behavior of various compounds in different conditions.
