How to Make Carbonic Acid, Properties and Uses - WorldOfChemicals

Carbonic Acid: Occurrence, Preparation, Properties and Uses

Carbonic acid

Carbonic Acid

Carbonic acid is a chemical compound with the chemical formula as H2CO3 and molecular formula as CH2O3. It is an inorganic weak acid, which exists only as a solution. Carbonic acid is also known as acid of air, aerial acid or dihydrogen carbonate. It forms two kinds of salts: carbonates and bicarbonates. Ph of carbonic acid is 4.68 in 1mM.

Carbonic acid is specifically diprotic acid, which means that it has two protons which can disassociate from the parent molecule. Thus, have two disassociation constants, first for bicarbonate ion disassociation and second for disassociation of the bicarbonate ion into the carbonate ion.


Carbonic acid is present in blood in the human body. It is formed in the human body when water gets dissolved with carbon dioxide. It is also present in rainwater, calcite, fermentation, coal, groundwater, meteors, volcanoes, amino acids, proteins, oceans, plants, erythrocytes, sulphur deposits, salts, and caves.


Properties of Carbonic Acid:

Physical Properties:

  1. Appearance: Grayish white solid.

  2. Melting point: 210 Celsius, boiling point: -78 degree Celsius.

  3. Molecular weight: 62.024 g/mol.

  4. Solubility: Insoluble.

  5. Carbonic acid has a pH value of less than 7.

  6. Carbonic acid is odorless and has the alkaline taste.


Chemical Properties:

  1. Carbonic acid is weak and unstable dibasic acid.

  2. It has an acidity of 6.3 pK.


Preparation of Carbonic acid:


  1. Calcium carbonate

  2. Hydrochloric acid solution

  3. Litmus

  4. Water


Wear lab goggles and try to avoid skin contact with hydrochloric acid. Follow general safety recommendations.

Steps involved:

  1. Pour some amount of water into the beaker.
  2. Add 5-6 drops of litmus in the beaker.
  3. Put a piece of calcium carbonate into a test tube or into some glass.
  4. Pour a little amount of hydrochloric acid into the test tube/glass and close the opening of it with a stopper with an outlet tube.
  5. Put the end of the outlet tube into the litmus solution. The gas which gets produced will start to bubble through the solution and the solution color will change.
  6. Test the pH of the water. There is no more water, carbonic acid has been produced. The pH will read it as a mild acid.

Chemical reaction in the form of an equation:

CaCO3 + HCl  CaCl2 + CO2 ↑+ H2O

CO2 + H2O → H2CO3

Carbonic Acid Uses:

  1. The most common use of carbonic acid is in the form of salts.

  2. In blood: Bicarbonate a form of carbonic acid salt acts as an intermediate for transporting CO2 out of the body through the respiratory gas exchange. It also plays a vital role in protonating a lot of nitrogen bases in blood serum. Carbonic acid is the main buffering element in the human body and is broken down into carbon dioxide by an enzyme called carbonic anhydrase. 
  3. In drinks: Carbonic acid is widely used in making bubbly, fizzy drinks.

  4. For treating dermatitides: it is typically used to treat dermatitides like ringworm.

  5. It is also used as a mouthwash or for vaginal douche.

  6. In case of poisoning or drug overdose carbonic acid is given orally for inducing vomiting.

  7. For cleaning contact lenses carbonic acid is very effective, it is also used as a gas for welding, food processing, and cosmetics.

  8. For hydrolysis of starch also carbonic acid is used. uses cookies to ensure that we give you the best experience on our website. By using this site, you agree to our Privacy Policy and our Terms of Use. X