Question

Oxalic acid is $26.68\% $ carbon, $2.24\% $ hydrogen, and the remainder oxygen, what is the empirical formula?

Answer 1

Hint: Empirical formula is a formula that gives the proportions of the elements present in a compound but not the actual numbers or arrangement of atoms. An empirical formula makes no mention of the arrangement or number of atoms. It is standard for many ionic compounds. We calculate the empirical formula for oxalic acid by following a couple of steps. For further information refer to the solution part.

Complete answer:
The empirical formula of a chemical compound is the simplest positive integer ratio of atoms present in a compound.
To calculate the empirical formula for any compound we must follow the following steps:
In any empirical formula problem you must first find the mass $\% $ of the elements in the compound.
Then change the $\% $ to grams.
Next, divide all the masses by their respective molar masses.
Pick the smallest answer of moles and divide all figures by that.
Assume $100g$ of acid. Now we breaking it down into its components, there are
$ \Rightarrow \dfrac{{26.68g}}{{12.01gmo{l^{ - 1}}.C}};\dfrac{{2.24g}}{{1.00794gmo{l^{ - 1}}.H}};\dfrac{{71.08g}}{{16.00gmo{l^{ - 1}}}}$
$ \Rightarrow C:H:O = 2.22:2.22:4.44$
$ \Rightarrow 1:1:2$
Therefore, the empirical formula of oxalic acid $CH{O_2}$.

Additional information:
Empirical formulas are the simplest form of notation. They provide the lowest whole-number ratio between the elements in a compound. Unlike molecular formulas, they do not provide information about the absolute number of atoms in a single molecule of a compound.

Note:
Remember empirical formula and molecular formula are different. An empirical formula represents the simplest whole-number ratio of various atoms present in a compound. The molecular formula shows the exact number of different types of atoms present in a molecule of a compound.