Alcohol and water both have strong tendency to form intermolecular hydrogen bonding. On mixing the two, a solution is formed as a result of formation of H-bonds between alcohol and `H_(2)O` molecules but these interactions are weaker and less extensive than those in pure `H_(2)O`. thus they show a positive deviation from ideal behaviour. As a result of this, the solution of alcohol and water will have higher vapoure pressure and lowever boiling point than that of water and alcohol.
