For hydrogen peroxide H2O2,
why he 2's are not cancelled.
Why it is not just HO?
What is special about it?
Hydrogen peroxide contains two atoms of hydrogen and two atoms of oxygen. Hence, its chemical formula would be H2O2. HO, would be the empirical formula of hydrogen peroxide, and we know that empirical formula gives the simplest ratio of atoms of different elements present in a molecule of the compound. It does not indicate the actual number of atoms present. Hence, it would be incorrect to write OH instead of H2O2. Moreover, H2O2 consists of peroxide ion denoted by O22- whose valency is 2 and H+ ion whose valency is 1. Hence, no cancellation is possible here.