Why does water rust a nail quicker than any other liquid?
Rust is the result of either atmospheric attack or electrolytic action upon ferrous material and is active when moisture in the form of water is present. Water is hydrogen oxide (it is, after all, H20) and the presence of oxygen in the water and in the atmosphere increases the rate of oxidation of the metal. Other liquids contain little or no oxygen and shield the iron from attack by oxygen, thus no or little oxidation occurs.