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What is Carbonic Acid?

M.R. Anglin
M.R. Anglin

Carbonic acid is a weak acid that is created when carbon dioxide (CO2) is dissolved in water (H2O), resulting in the chemical formula H2CO3. When the acid dissociates, or gives up a hydrogen ion, the resulting molecule is called a bicarbonate ion. Carbonic acid appears frequently in the natural world. It can be found in sodas, champagne, and blood. The acid even appears in rain.

During the making of soda, carbon dioxide is dissolved in water. As stated, this process also creates carbonic acid. This acid, along with phosphoric acid and other acids, provides the tart taste in many sodas. It also provides a slight burning sensation that a person feels when ingesting a fizzy drink. Thus, it is the acid that makes fizzy drinks taste fizzy.

Carbonic acid is added to drinks like soda to make them taste fizzy.
Carbonic acid is added to drinks like soda to make them taste fizzy.

Carbonic acid plays an important role in keeping the body’s pH stable. The normal pH of bodily fluids is around 7.4 and must be kept close to this value in order for the body to function properly. If the pH changes, whether up or down, enzymes can stop functioning, muscles and nerves can start weakening, and metabolic activities becomes impaired. The bicarbonate ion released from acid serves as a buffer that helps resist changes in pH. This means it can act as an acid or a base as the need arises.

Acids are defined as any substance that releases hydrogen ions into solutions. Bases are substances that accept those hydrogen ions. When excess hydrogen ions build up in the body — i.e. the fluids become more acidic — then bicarbonate ions accepts those extra hydrogen ions and keeps the body’s pH at a normal level. In the inverse, if the hydrogen ion levels drop too much — i.e. the fluids become too alkaline — then carbonic acid gives up hydrogen ions in order to keep the blood’s pH normal. This process is also seen during the transport of oxygen and carbon dioxide.

Carbonic acid even appears as a normal occurrence in rain. As rainwater falls through the air, it absorbs carbon dioxide, producing carbonic acid. Thus, when it reaches the ground, it has a pH of about 5.5. This should not be confused with acid rain which is caused when emissions, such as sulfur oxides and nitrogen oxides, from burning fossil fuels rises to the air. As it falls, rain absorbs these components, producing acids which can make the pH in rain fall to as little as two.

Discussion Comments


So wait, the carbon dioxide can make the carbonic acid in our bodies, right? Just asking, but is this what causes pneumonia?


Does carbon leach from carbonic acid?


Yes, carbonic acid can store carbon. Our oceans are constantly recycling carbon.


What are the physical properties of carbonic acid?


What is the pH of carbonic acid?


CaCO3 is made when mixing H2CO3 together and you have a production of H2(g).


what is made if i add calcium to carbonic acid ?


No, H2CO3 doesn't carbonate (make fizzy) the blood. Our body has to keep the Ph at a very tight level and it pulls upon various resources to keep the blood's H2CO3 level right on. One of the roles the Carbonic Acid plays is it can leach the calcium from the bones to change the Ph. Our bodies can cause various other systems to change functions till things get regulated also.

If you note, the author stated it changes to bicarbonate, meaning the Carbonic Acid can give up its carbon to take care of acid situations, and it can give up its hydrogen atom to take care of alkaline.


Does H2CO3 carbonate the blood? Does this alter the nutrients in the blood? Please advise.


Can carbonic acid be used in carbon capture and storage?

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    • Carbonic acid is added to drinks like soda to make them taste fizzy.
      By: karandaev
      Carbonic acid is added to drinks like soda to make them taste fizzy.