Answer:
Formation of intermolecular hydrogen bonding between water molecules and molecules of n-butanol
Step-by-step explanation:
Low molecular weight alcohols are miscible with water in all proportions. The reason for this is that, when a low molecular weight alcohol is dissolved in water, intermolecular hydrogen bonds are formed between the low molecular weight alcohol and water molecules.
Low molecular weight alcohols such as n-butanol contain the polar -OH group which interacts with water via hydrogen bonding.