Hydrogen peroxide is a chemical compound with the formula H2O. When it is in its purest form, it is a colorless liquid, which is a little more viscous than water and for safety it is used as an aqueous solution. It is the simplest peroxide and can be used as a disinfectant, oxidizer and bleaching agent. It is usually called as being water but contains an additional oxygen atom. When pure hydrogen peroxide is heated to boiling point, it will explode and when comes in contact with skin, it will cause irritation. It is for this reason it is used in diluted form.