What is the relation between Solubility and Boiling point alcohol ?
Answers
Answer:
Alcohols are soluble in water. This is due to the hydroxyl group in the alcohol which is able to form hydrogen bons with water molecules. Alcohols with a smaller hydrocarbon chain are very soluble. As the length of the hydrocarbon chain increases, the solubility in water decreases. With four carbon in the hydrocarbon chain and higher, the decrease in solubility becomes visible as the mixture forms two immiscible layers of liquid. The reason why the solubility decreases as the length of hydrocarbon chain increases is because it is requires more energy to overcome the hydrogen bonds between the alcohol molecules as the molecules are more tightly packed together as the size and mass increases.

In the image above, the partially negative oxygen atom in the ethanol molecule forms a hydrogen bond with the partially positive hydrogen atom in the water molecule.
Boiling point

This graph shows the comparison of boiling points of methane with methanol, ethane with ethanol, propane with propanol, and butane with butanol.
From the graph we can see that the boiling point of an alcohol is always much higher than the boiling point of the corresponding alkane with the same hydrocarbon chain. The boiling point of alcohols also increase as the length of hydrocarbon chain increases.
The reason why alcohols have a higher boiling point than alkanes is because the intermolecular forces of alcohols are hydrogen bonds, unlike alkanes with van der Waals forces as their intermolecular forces.
The image below shows ethanol molecules with a hydrogen bond.