To arrange the compounds acetaldehyde, propane, propanone, acetic acid, and ethyl alcohol in increasing order of their boiling points, we need to consider their molecular structures and intermolecular forces.
The key factor influencing boiling points is the strength of intermolecular forces.
Here's how these compounds compare:
Ethyl Alcohol (Ethanol):
- It can form hydrogen bonds due to the presence of the hydroxyl (-OH) group.
- Hydrogen bonding is a relatively strong intermolecular force.
- Ethanol will have a relatively high boiling point.
Acetic Acid:
- Like ethanol, acetic acid can also form hydrogen bonds due to the presence of the carboxyl (-COOH) group.
- It will have a higher boiling point than compounds without hydrogen bonding.
Propanone (Acetone):
- Propanone can't form hydrogen bonds but can have dipole-dipole interactions.
- It has a lower boiling point compared to ethanol and acetic acid but is still higher than some of the other compounds.
Acetaldehyde:
- It can form dipole-dipole interactions but not as strong as hydrogen bonds.
- It will have a boiling point lower than ethanol, acetic acid, and propanone but higher than propane.
Propane:
- Propane is a nonpolar molecule and only experiences weak dispersion forces (Van der Waals forces).
- It will have the lowest boiling point among these compounds.
So, the expected order of boiling points from lowest to highest is:
propane < acetaldehyde < propanone < acetic acid < ethyl alcohol.
Now, let's determine the compounds expected to be at the third and fourth positions:
- Third Position: Propanone (Acetone) is expected to be at the third position.
- Fourth Position: Acetic Acid is expected to be at the fourth position.
