Question

Write the empirical formula for the following:
${{H}_{2}}{{O}_{2}}$

Answer 1

Hint: A molecular formula of any compound shows the exact number of atoms in that compound. Empirical formula is derived from molecular formula as it shows the simplest whole number ratio of the atoms present in a molecule. Molecular formula is ‘n’ times the empirical formula. Where ‘n’ is molecular mass upon empirical formula mass.

Complete answer:
A chemical compound is represented by the atoms present in that compound. This is done through the molecular formula of that compound. The molecular formula tells the exact number of atoms in any compound or molecule.
Empirical formula is different from molecular formula. Empirical formula for any compound can be derived by its molecular formula, as it is the simplest whole number ratio of atoms present in any compound.
We have been given hydrogen peroxide ${{H}_{2}}{{O}_{2}}$ and to find its empirical formula. As hydrogen atoms are present in an amount of two that is equal to the number of oxygen atoms that is 2, so it will have the ratio 1:1 that will lead to the empirical formula being HO.
Hence, the empirical formula of ${{H}_{2}}{{O}_{2}}$ is HO.

Note:
For determining the empirical formula of complex compounds there is a relationship that is molecular formula = empirical formula $\times $ n, where n = $\dfrac{molecular\,mass}{empirical\,formula\,mass}$. Also from the percentage of atoms we can find it by dividing the % of each atom by their atomic mass, then dividing the numbers by the smallest number, and multiplying these values by a suitable number to get the simplest whole number ratio.