Question

Alcohols are comparatively more soluble in water than hydrocarbons of comparable molecular masses. Explain this fact.

Answer 1

Hint: We have to remember that the organic compounds which comprises a hydroxyl group that is covalently linked to a carbon atom $R - OH$. Alkanes are similar to alcohols i.e. they contain long or short chains of carbon atoms surrounded by hydrogen atoms. There is less intermolecular association due to the non-polar carbon-hydrogen bond.

Complete answer:
We need to know that the alcohols have strong intermolecular hydrogen bonding. The $OH$ group present in the alcohol allows the molecules to participate in hydrogen bonding. A larger amount of energy is needed to break the intermolecular hydrogen bonding in alcohols hence; they contain higher boiling and higher melting points when compared to hydrocarbons of comparable molar mass.
On the other hand, alkanes are insoluble in water because of their non-polar nature. The majority of their bonds are nonpolar covalent carbon-hydrogen linkages. The lack of strong intermolecular forces in alkane results in the lower solubility of hydrocarbons compared to alcohols.
For example, take the example of 2-butanol and 2-methylbutane.

In 2-butanol, there is a strong intermolecular hydrogen bonding. The presence of hydroxyl groups permits the alcohol to take in the hydrogen bonding. A larger amount of energy is needed to break the hydrogen bonding in alcohols. Whereas, in 2-methylbutane there is no intermolecular hydrogen bonding and bonds are nonpolar covalent between carbon-hydrogen bonding. This absence of intermolecular hydrogen bonding results in the lower solubility of alkanes.

Note:
We can use alcohols in,
-As an ingredient in alcoholic beverages such as beer and wine.
-Used in the production of methylated spirit
-Used as a fuel
-Used as solvent
We can use alkanes in,
-Used for generating electricity
-Used as vehicle fuel
-Used in explosions and special effects.