Final answer:
Methanol is the most soluble alcohol in water among the listed options due to its shortest carbon chain, enabling it to form hydrogen bonds with water molecules easily.
Step-by-step explanation:
When considering the solubility of alcohols in water, we need to look at the alcohol's ability to engage in hydrogen bonding with water molecules. The smallest alcohols, such as methanol, ethanol, and propanol, are entirely soluble in water. This is because the hydroxyl (-OH) group in these alcohols can form hydrogen bonds with water molecules. However, as the length of the carbon chain increases, the nonpolar alkyl part of the molecule becomes more dominant, and the solubility in water decreases. Among the listed alcohols - ethanol, methanol, propanol, and butanol, methanol has the shortest carbon chain and is therefore the most soluble in water. It can mix with water in all proportions, while the others have increasingly longer carbon chains and consequently lower solubility in water.