Difference Between Formic Acid and Acetic Acid

Main Difference – Formic Acid vs Acetic Acid

Both formic acid and acetic acid are organic molecules that can be categorized as carboxylic acids due to the presence of a carboxyl group. Therefore, both compounds are acidic compounds. However, in aqueous solutions, these are weak acids that are partially dissociated into their conjugated base form by releasing a proton. The main difference between formic acid and acetic acid is that formic acid is composed of a carboxyl group attached to a hydrogen atom whereas acetic acid is composed of a methyl group attached to a carboxyl group.

Key Areas Covered

1. What is Formic Acid
      – Definition, Properties, and Applications
2. What is Acetic Acid
      – Definition, Properties, and Applications
3. What are the Similarities Between Formic Acid and Acetic Acid
      – Outline of Common Features
4. What is the Difference Between Formic Acid and Acetic Acid
      – Comparison of Key Differences

Key Terms: Acetic Acid, Carboxyl Group, Carboxylic Acid, Ethanoic Acid, Formic Acid, Methanoic Acid,

Difference Between Formic Acid and Acetic Acid - Comparison Summary

What is Formic Acid

Formic acid is a carboxylic acid that has the chemical formula CH2O2. IUPAC name for formic acid is methanoic acid. The molar mass of formic acid is about 46 g/mol. At room temperature and pressure, formic acid is a colorless liquid that has a pungent odor. The melting point and boiling point of formic acid are 8.4oC and 100.8oC, respectively.

Formic acid is completely miscible in water since it can form strong hydrogen bonds with water molecules. Formic acid can form dimers. Dimers are chemical species composed of two molecules of the same compound attracted to each other through intermolecular attractions forces. In formic acid solutions, formic acid molecules form dimers through intermolecular hydrogen bonds.

Difference Between Formic Acid and Acetic Acid

Figure 1: Formic Acid Dimers

Formic acid can be observed naturally in some ant species. It can also be found as a component in the atmosphere. Formic acid is used as a preservative and an antibacterial agent. Due to its acidity, formic acid is also used in leather industry as a coagulant.

What is Acetic Acid

Acetic acid is a carboxylic acid that has the chemical formula C2H4O2. The molar mass of acetic acid is about 60 g/mol. It appears as a colorless liquid at room temperature and pressure. It has a vinegar-like odor. The melting point of acetic acid is about 17oC, and the boiling point is about 119oC. It is totally soluble in water since it is capable of forming strong hydrogen bonds with water molecules. The IUPAC name for acetic acid is ethanoic acid.

Main Difference - Formic Acid vs  Acetic Acid

Figure 2: Chemical Structure of Acetic Acid

Acetic acid is capable of releasing protons attached to the oxygen atom in its hydroxyl group (-OH). Acetic acid also can form dimers. Two acetic acid molecules can be attracted to each other through the formation of hydrogen bonds. This attachment of two molecules is called the formation of a dimer.

There are a number of uses of acetic acid. It is a major component of vinegar, which is a liquid used for cooking purposes, cleaning and many other household needs. In addition, acetic acid is used to produce vinyl acetate monomer. Acetic acid is also a starting material for the production of esters.

However, concentrated acetic acid or long term exposure to acetic acid can cause skin burns since it is an acid. Moreover, it can cause tissue destruction. Therefore, it is very important to take care when handling acetic acid.

Similarities Between Formic Acid and Acetic Acid

  • Formic acid and acetic acid are carboxylic acids.
  • They can form dimers.
  • Both are well soluble in water.
  • Both can form hydrogen bonds.
  • Both are colorless liquids at room temperature.
  • Both have a pungent odor.

Difference Between Formic Acid and Acetic Acid

Definition

Formic Acid: Formic acid is a carboxylic acid that has the chemical formula CH2O2.

Acetic Acid: Acetic acid is a carboxylic acid that has the chemical formula C2H4O2.

Structure

Formic Acid: Formic acid is composed of a carboxyl group attached to a hydrogen atom.

Acetic Acid: Acetic acid is composed of a methyl group attached to a carboxyl group.

IUPAC Name

Formic Acid: The IUPAC name for formic acid is methanoic acid.

Acetic Acid: The IUPAC name for acetic acid is ethanoic acid.

Molar Mass

Formic Acid:  The molar mass of formic acid is 46 g/mol.

Acetic Acid: The molar mass of acetic acid is 60 g/mol.

Boiling Point

Formic Acid: The boiling point of formic acid is about 100.8oC.

Acetic Acid: The boiling point of acetic acid is about 119oC.

Conclusion

Formic acid and acetic acid are important chemicals in household needs as well as in industrial scale applications. They share some similar characteristics. But there are some considerable differences between these compounds. The main difference between these compounds is that formic acid is composed of a carboxyl group attached to a hydrogen atom whereas acetic acid is composed of a methyl group attached to a carboxyl group.

References:

1. Garcia, Nissa. “What is Acetic Acid? – Uses, Structure & Formula.” Study.com, Available here. Accessed 31 Aug. 2017.
2. Brown, William H. “Formic acid (HCO2H).” Encyclopædia Britannica, Encyclopædia Britannica, inc., 27 May 2015, Available here. Accessed 31 Aug. 2017.
3. “Formic acid.” Wikipedia, Wikimedia Foundation, 29 Aug. 2017, Available here. Accessed 31 Aug. 2017.

Image Courtesy:

1. “Formic Acid Hydrogenbridge V.1″ By Jü – Own work (CC0) via Commons Wikimedia
2. “Acetic-acid” (Public Domain) via Commons Wikimedia

About the Author: Madhusha

Madhusha is a BSc (Hons) graduate in the field of Biological Sciences and is currently pursuing for her Masters in Industrial and Environmental Chemistry. Her interest areas for writing and research include Biochemistry and Environmental Chemistry.

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