Question

The formula for the oxalate ion is $C_2{O_4}^{2-}$. What would you predict the formula for oxalic acid to be?

Answer 1

Hint: An ion is a net electrically charged particle, atom, or molecule. By convention, the electron's charge is regarded as negative. By convention, an electron's negative charge is equal to and opposite that of charged proton(s) deemed positive. An ion's net charge is non-zero because its total number of electrons is greater than its total number of protons. An anion is a negatively charged ion with more electrons than protons, whereas a cation is a positively charged ion with less electrons. Cations and anions are attracted to one other by their opposing electric charges and easily form ionic compounds.

Complete answer:
The Hill system is a method of writing empirical chemical formula, molecular chemical formulae, and condensed formula components in which the number of carbon atoms in a molecule is written first, followed by the number of hydrogen atoms, and finally the number of all other chemical elements, in alphabetical order of chemical symbols. When there is no carbon in the formula, all of the elements are given alphabetically, including hydrogen. By ranking formulas based on the amount of atoms of each element included in the formula using these criteria, changes in earlier elements or numbers are considered as more significant than discrepancies in later elements or numbers.
An acid is made up of hydrogen ion(s) that are positively charged and an anion. $$n{H}^{+}+A^{-n}\to H_{n}A$$ is a chemical equation that represents this.
The Hill System may also be used to identify the order in which elements should be placed in a chemical formula.
"The Hill system (or Hill notation) is a method of writing empirical chemical formulas, molecular chemical formulas, and condensed formula components in which the number of carbon atoms in a molecule is written first, followed by the number of hydrogen atoms, and finally the number of all other chemical elements in alphabetical order. When there is no carbon in the formula, all of the elements are given alphabetically, including hydrogen."
Hence $H_2{C}_2{O}_4$ is the correct answer.

Note:
Oxalic acid is an organic acid having the formula $H_2{C}_2{O}_4$ and the IUPAC name ethanedioic acid. It is the most basic of the dicarboxylic acids. It's a white crystalline solid that dissolves in water to create a colourless solution. It gets its name from the fact that oxalic acid was first extracted from flowering plants of the genus Oxalis, sometimes known as wood-sorrels. Although oxalic acid is found naturally in many foods, it can be harmful if consumed in large amounts or when skin contact is sustained.