Question

What are the empirical and molecular formulas of maleic acid?

Answer 1

As we know that empirical formula of a chemical compound is the simplest positive integer ratio of atoms present in a compound whereas molecular formula (also known as chemical formula) tells us about the number of atoms of each element present in the same chemical compound. Here we are asked about the empirical and molecular formulas of maleic acid.

Complete answer:
Let us first understand the basic definition of empirical and molecular formulas which will help us to answer the following question:-
Empirical formula: This formula tells us about the relative ratios of different atoms in a molecule or a compound and these ratios hold true on the molar level as well. This formula does not help us in making the actual structure of the molecule or compound as we do not know the number of atoms of each element present in that very molecule or compound.
Molecular formula: It is also known as chemical formula and tells us about the number of atoms of each element present in a molecule or a compound. This formula helps us in making the actual structure of the molecule or compound as we know the number of atoms of each element present in that very molecule or compound.
Maleic acid is a cis-butenedioic acid. The molecular formula or chemical formula of maleic acid is: ${{C}_{4}}{{H}_{4}}{{O}_{4}}$. This tells us that there are 4 carbon atoms, 4 hydrogen atoms and 4 oxygen atoms present in this given compound.
As we know that the empirical formula is derived by finding the greatest common factor among subscripts in the molecular formula and in case of${{C}_{4}}{{H}_{4}}{{O}_{4}}$, it is 4. So let us take the simplest ratio by dividing all the subscripts by 4 to get the empirical formula of maleic acid as shown below:-
${{C}_{4/4}}{{H}_{4/4}}{{O}_{4/4}}$ = CHO
Therefore the empirical formula of maleic acid is CHO and the molecular formula is ${{C}_{4}}{{H}_{4}}{{O}_{4}}$.

Note:
-Remember that maleic acid is the cis isomer of butenedioic acid whereas fumaric acid is the trans isomer of butenedioic acid which means it have the same empirical and chemical formula as that of maleic acid.
-Also maleic acid has more solubility than fumaric acid in water.