Rusting Nails

We investigate the conditions needed for rust to form. Four iron nails are placed under different conditions. One is half submerged in water. Another is completely submerged in boiled water. One is half submerged in salt water. The final one is sealed in a boiling tube with anhydrous calcium chloride. The results show that both oxygen and water are required for rusting to occur. Chemistry - Reactions - Learning Points. Water and oxygen must both be present for iron to rust. The presence of ions increases the rate at which iron rusts. Rust is iron(III) oxide, which is insoluble. Iron rusts because it loses electrons or is "oxidised". Oxygen and water accept electrons during the process of corrosion; we say that oxygen and water molecules are reduced, forming hydroxide ions. Iron will not rust if an external agent like a more reactive metal returns the lost electrons to the iron; this is known as sacrificial protection. A Twig Experiment Film. Let students experience real experiments in lab conditions anywhere, from setup, method all the way through to analysis and real-world application.