How does solubility of alcohols change with increasing chain length?

The solubility of alcohols in water generally decreases as the chain length of the alcohol increases. This trend can be attributed to the structural characteristics of alcohol molecules.

Short-chain alcohols, like methanol and ethanol, have a relatively small hydrophobic hydrocarbon tail and a hydroxyl (-OH) group that can hydrogen bond with water molecules, making them capable of dissolving well in water. As the hydrocarbon chain becomes longer, the hydrophobic (water-repelling) character of the molecule increases, while the proportion of the molecule that can interact favorably with water through hydrogen bonding decreases.

In longer-chain alcohols, the impact of the hydrophobic hydrocarbon section outweighs the influence of the hydrophilic hydroxyl group, leading to lower solubility in water. This results in a trend where longer-chain alcohols are less soluble than their shorter-chain counterparts.