Flexi Says: Normally, when a liquid is heated, it starts to convert into a gaseous state at its boiling point. However, the liquid part of an egg solidifies on heating. When an egg is boiled, the bonds in the egg proteins break and then form new bonds with other proteins. In the process, water molecules surrounding each protein molecule are forced out. This turns the egg solid. The process of boiling an egg is thus a chemical change because the process is not reversible.
