This experiment will explore the rusting of iron nails over a period of 7 days in liquids with different pH readings. For the sake of this experiment I will use solutions lemon juice (pH- 2), tomato juice (pH- 4), milk (pH- 6), water (pH -7), sea water (pH- 8), milk of magnesia (pH- 10) and Soapy water (pH- 12). An iron nail will be submerged in 15 mL of each of these solutions for 7 days. The results will be measured by the weight of the nail before and after. Iron is a chemical element with symbol Fe and atomic number 26. It is a metal that is usually prone to rusting, Iron and steel rust when they come into contact with water and oxygen, When they come in contact with each other, the iron loses electrons to oxygen atoms, this is called oxidation. A coating of Iron Oxide forms on the outer layer of the iron which acts as a barrier to further rusting. Rust is usually a red/brown colour that coats the iron which eventually flakes off. Corrosion is the chemical reaction where metals break down slowly due to the elements present in their environment. Rusting, is a quite slow version of corrosion, it is the breakdown of a metal, in this case, iron. The chemical equation of rusting is;
4Fe + 3O2 ? 2Fe2O
In modern science rusting is usually prevented, there are two main methods that work as prevention of rust, these include, barrier protection, this is a method which involves a coating of a substance which protects the iron from the atmospheric air and Galvanization, this is where a more reactive metal, usually zinc, is used to coat the iron, the zinc loses its electrons, or rusts acting as a barrier to the metal underneath.
pH is an important part of this experiment as the different levels of pH that can range from 0-14 will all have different effects on the corrosion of iron. pH is a measure of the acidity or alkalinity of a solution, it is referred to on a scale from 1 – 14 where 7 is neutral, not acidic nor alkaline, values lower than 7 are more acidic and values higher than 7 are more alkaline. To alter the pH concentration in a liquid, dilution may occur.
This experiment explores the chemistry branch of science, more specifically chemical reactions involving corrosion. There are many reasons this experiment would be explored for ‘real world’ reasons, iron is used in buildings and infrastructure, where it is exposed to different environments involving pH solutions. Builders may find this experiment helpful as it may show what conditions or liquids iron nails would be able to with hold regarding the pH of the liquid.
There have been similar investigations carried out such as, http://gmsstemfairnelias.weebly.com/conclusion.html, this experiment explored the The effect of pH level on corrosion of an iron nail, the results showed “The general relationship seen the two variables was that the lower the pH, the higher the loss of weight of the nails, indicating that corrosion is accelerated by higher acidity.”