How does the solubility of alcohols in water change with increasing carbon chain length?

• A. Short-chain alcohols are miscible with water; longer chains have reduced solubility due to non-polar hydrocarbon parts
• B. Short-chain alcohols are insoluble in water; longer chains become more soluble
• C. All alcohols are equally soluble in water
• D. Solubility is not affected by chain length

Answer: (A)

The key idea is that solubility in water depends on the balance between the polar OH group and the non-polar hydrocarbon chain. The hydroxyl group can form hydrogen bonds with water, so small alcohols mix in all proportions with water. But as the carbon chain gets longer, the non-polar part grows and water can’t interact as effectively with the molecule, making it less soluble. So short-chain alcohols are miscible with water, while longer-chain alcohols have progressively reduced solubility due to the increasing non-polar hydrocarbon portion.