Difference Between Oxalic Acid and Acetic Acid

The key difference between oxalic acid and acetic acid is that oxalic acid has two carbonyl carbon centers whereas acetic acid has one carbonyl carbon center.

Oxalic acid and acetic acid are organic compounds having carbon, hydrogen and oxygen atoms in their molecules. These two acidic compounds have some similarities due to the presence of carbonyl carbon centers.

CONTENTS

1. Overview and Key Difference
2. What is Oxalic Acid 
3. What is Acetic Acid
4. Side by Side Comparison – Oxalic Acid vs Acetic Acid in Tabular Form
5. Summary

What is Oxalic Acid?

Oxalic acid is an organic compound having the chemical formula H2C2O4. This compound occurs as a colourless solid which easily dissolves in water. Oxalic acid is a dicarboxylic acid because it is a combination of two carboxylic acid groups; in fact, it is the simplest dicarboxylic acid. Furthermore, it has a high acid strength and is a strong reducing agent. The conjugate base of this acid is oxalate ion. Generally, the oxalic acid occurs in the dihydrate form. Moreover, it naturally occurs in some food. The molar mass of the anhydrous form is 90 g/mol.

We can prepare oxalic acid from the oxidation of carbohydrates or glucose using nitric acid or air in the presence of vanadium pentoxide. There are two polymorphs of oxalic acid where one polymorphic structure has a chain-like structure due to the presence of hydrogen bonds while the other polymorphic structure is in the sheet-like structure.

When considering the uses of oxalic acid, it is useful in cleaning and bleaching purposes, as a reagent in extractive metallurgy, useful in aluminum anodizing process, etc.

What is Acetic Acid?

Acetic acid is an organic compound having the chemical formula CH₃COOH. It is the second simplest carboxylic acid. This acid occurs as a colourless liquid having a pungent, vinegar-like odour. Furthermore, acetic acid has a distinctive sour taste as well. This compound has a methyl group attached to a carboxylic acid. It is a weak acid because it dissociates partially in an aqueous solution. The molar mass of acetic acid is 60.05 g/mol. The conjugate base of this acid is acetate ion. Moreover, the systemic IUPAC name of acetic acid is ethanoic acid.

In its solid form, acetic acid form chains by interconnecting the molecules through hydrogen bonds. In its vapour phase, there are dimers of acetic acid. Furthermore, in its liquid state, it is a hydrophilic protic solvent. Moreover, at physiological pH conditions, this compound exists in a fully ionized form as acetate. We can produce acetic acid in both synthetic and bacterial fermentation routes. In addition to these, in the synthetic route, acetic acid is produced via methanol carbonylation.

We can produce acetic acid industrially in synthetic routes or via biological routes. For example, we can produce acetic acid through the carbonylation of methanol, and we can produce this acid via fermentation of seeds such as apple cider, using potato mash, rice, etc.

What is the Difference Between Oxalic Acid and Acetic Acid?

Oxalic acid and acetic acid are two types of carboxylic acid compounds. The key difference between oxalic acid and acetic acid is that oxalic acid has two carbonyl carbon centers whereas acetic acid has one carbonyl carbon center. Therefore, oxalic acid is a dicarboxylic acid whereas acetic acid is a monocarboxylic acid.

Moreover, oxalic acid is produced via the oxidation of carbohydrates or glucose using nitric acid or air in the presence of vanadium pentoxide while acetic acid is produced using both synthetic and bacterial fermentation routes.

Below infographic presents more details of the difference between oxalic acid and acetic acid.

Summary – Oxalic Acid vs Acetic Acid

Oxalic acid and acetic acid are two types of carboxylic acid compounds. The key difference between oxalic acid and acetic acid is that oxalic acid has two carbonyl carbon centers whereas acetic acid has one carbonyl carbon center.

Reference:

1. “Acetic Acid.” National Center for Biotechnology Information. PubChem Compound Database, U.S. National Library of Medicine, Available here.

Image Courtesy:

1. “Oxalsäure2” By NEUROtiker – Own work (Public Domain) via Commons Wikimedia
2. “Acetic-acid-2D-skeletal” (Public Domain) via Commons Wikimedia