CARBONIC ACID

Carbonic acid is a weak inorganic acid with the chemical formula H₂CO₃, formed when carbon dioxide (CO₂) dissolves in water.
Carbonic acid exists mainly in aqueous equilibrium with bicarbonate (HCO₃⁻) and carbonate (CO₃²⁻) ions and cannot be isolated as a stable pure compound under normal conditions.
Carbonic acid plays a critical role in natural waters and biological systems, especially in blood pH regulation through the bicarbonate buffer system.

CAS Number: 463-79-6
Molecular Formula: CH2O3
Molecular Weight: 62.02

Synonyms: carbonic acid, 463-79-6, Dihydrogen carbonate, H2CO3, DTXSID9043801, CHEBI:28976, Acid, Carbonic, RefChem:6524, DTXCID7023801, 610-295-3, 682-330-0, hydroxy ketone, hydroxy-ketone, Acidosan, component of Col-Evac, component of Pretts, carbonicacid, dihydroxyketone, hydroxyketone, Koehlensaeure, hydroxyl ketone, Carbonic acid-, hydrogen bicarbonate, hydrogencarbonic acid, dihydroxidooxidocarbon, hydroxycarboxylic acid, hydrogentrioxocarbonate, BCT, SCHEMBL1179, NCIOpen2_000954, NCIOpen2_001122, NCIOpen2_001162, NCIOpen2_004622, SCHEMBL59134, 22719-67-1, SCHEMBL149823, CHEMBL1161632, [CO(OH)2], BDBM50147627, DB-318895, NS00070372, C01353, Q104334, Q27110274, Carbonic acid hydrogen;H2CO3;Yttrium Carbonate Dihydrate;Carbonic acid;carbonicaci

Carbonic acid plays a fundamental role in natural waters, including oceans, rivers, and rainwater, where it contributes to natural acidity.
Carbonic acid is responsible for the slight acidity of rain and is a key factor in chemical weathering processes such as the dissolution of limestone and other carbonate rocks.
Through these processes, carbonic acid is involved in long-term geological cycles, including the global carbon cycle.

In biological systems, carbonic acid is essential for maintaining acid–base balance, especially in human blood.
Carbonic acid functions as part of the bicarbonate buffer system, which helps regulate blood pH by rapidly converting between CO₂ and bicarbonate.
This reversible system allows the body to transport carbon dioxide efficiently from tissues to the lungs for exhalation.

Carbonic acid has the formulaH2CO3 (equivalently OC(OH)2). 
It is also a name sometimes given to solutions of CO2 in water
Carbonic acid is thought to exist on icy planetary bodies where CO₂ and water ice coexist, such as on Mars or icy moons.

This makes carbonic acid relevant not only to Earth chemistry but also to planetary and astrochemical research.
Carbonic acid plays a direct role in calcium carbonate precipitation and dissolution equilibria.
Carbonic acid controls the solubility of minerals such as calcite and aragonite by regulating carbonate ion availability.

This mechanism is critical in biomineralization processes, including shell and skeleton formation in marine organisms.
In water treatment systems, carbonic acid affects alkalinity and pH control.
Dissolved CO₂ forming carbonic acid can lower pH and influence coagulation, disinfection efficiency, and scaling behavior.

Engineers often manage carbonic acid levels to optimize water stability and prevent infrastructure damage.
Carbonic acid also has kinetic significance despite its low concentration.
The uncatalyzed hydration of CO₂ is slow, but in biological systems it is accelerated by carbonic anhydrase enzymes.

This rate enhancement is essential for rapid respiration and acid–base regulation in living organisms.
Carbonic acid is a chemical compound with the chemical formula H2CO3. 
The molecule rapidly converts to water and carbon dioxide in the presence of water.

In contrast to early-twentieth century textbooks, numerous studies conducted since ca. 
1990 identified H2CO3 as a real molecule with a distinct Raman spectrum and with a first-order life-time of ca. 20 ms at 37 °C.
Solid anhydrous carbonic acid has also been isolated.

Carbonic acid is a weak, diprotic inorganic acid with the chemical formula H₂CO₃, formed when carbon dioxide (CO₂) dissolves in water via a reversible hydration reaction that is fundamental to atmospheric chemistry, aquatic systems, and physiological processes in living organisms.
Carbonic acid exists mainly in aqueous equilibrium with its conjugate bases, bicarbonate (HCO₃⁻) and carbonate (CO₃²⁻) ions, and because it rapidly decomposes back into carbon dioxide and water, it cannot be isolated as a stable pure compound under normal laboratory or environmental conditions, instead remaining present only transiently in solution.
Carbonic acid plays a critical role in natural waters and biological systems, especially in blood pH regulation through the bicarbonate buffer system, where it helps control acid–base balance, facilitates carbon dioxide transport from tissues to the lungs, and maintains the narrow pH range required for proper enzymatic and cellular function.

Carbonic acid, (H2CO3), a compound of the elements hydrogen, carbon, and oxygen. 
It is formed in small amounts when its anhydride, carbon dioxide (CO2), dissolves in water.
Carbonic acid (ancient name acid of air or aerial acid) has the formula H2CO3. 

Carbonic acid is also a name sometimes given to solutions of carbon dioxide in water, which contain small amounts of H2CO3. 
The salts of carbonic acids are called bicarbonates (or hydrogencarbonates) and carbonates. 
Carbonic acid should not be confused with carbolic acid, an antiquated name for phenol.

Melting point: 211-212 °C(Solv: water (7732-18-5))
Boiling point: 333.6±25.0 °C(Predicted)
Density: 1.668±0.06 g/cm3(Predicted)
pka: 4.36±0.41(Predicted)
Stability: Cannot be isolated as a pure liquid or solid, since the products of its decomposition, carbon dioxide and water, are much more stable than the acid.

Carbonic acid is involved in carbon capture and storage (CCS) technologies.
Absorption of CO₂ into aqueous solutions temporarily forms carbonic acid before further chemical conversion or sequestration.
Understanding its kinetics helps optimize CO₂ absorption efficiency.

Carbonic acid is central to acid–base regulation and gas transport.
Carbonic acid forms part of the bicarbonate buffer system that maintains blood pH within a very narrow range.
The rapid interconversion between carbonic acid and bicarbonate allows efficient transport of carbon dioxide from tissues to the lungs for exhalation.

Carbonic acid is also important in industrial and everyday contexts.
Carbonic acid is responsible for the acidity and characteristic taste of carbonated beverages, where dissolved CO₂ forms carbonic acid.
In industrial processes, its chemistry is relevant to water treatment, corrosion phenomena, and carbon capture and storage technologies.

Carbonic acid, also known as H2CO3, is a carbon-containing molecule with the chemical formula H2CO3. 
A minor amount of this molecule can be found in carbon dioxide solutions including water. 
Because this molecule contains one carbon-oxygen double bond, its chemical formula can also be represented as OC(OH)2 due to the fact that it contains one carbon-oxygen double bond.

Carbonic acid is a carbon oxoacid and a chalcocarbonic acid. 
Carbonic acid has a role as a mouse metabolite. 
Carbonic acid is a conjugate acid of a hydrogencarbonate.

These values explain why bicarbonate dominates in physiological and natural water pH, while carbonate becomes important only in alkaline conditions.
This acid–base behavior is crucial for buffering systems in both environmental and biological contexts.
In atmospheric chemistry, carbonic acid formation is directly linked to carbon dioxide partial pressure.

An increase in atmospheric CO₂ shifts the equilibrium toward higher dissolved carbonic acid concentrations in oceans and surface waters.
This mechanism underlies ocean acidification, which affects coral calcification and marine ecosystems.

Carbonic acid also influences corrosion processes in aqueous environments.
In CO₂-rich water systems, such as pipelines and geothermal wells, carbonic acid accelerates the corrosion of steel and iron alloys.
This type of degradation, known as sweet corrosion, is a major concern in oil and gas industries.

According to quantum chemical calculations, at room temperature (300 K), pure carbonic acid is expected to be a kinetically stable gas.
There are two main methods to produce anhydrous carbonic acid: reaction of hydrogen chloride and potassium bicarbonate at 100 K in methanol and proton irradiation of pure solid carbon dioxide.
Chemically, it behaves as a diprotic Brønsted acid.

Carbonic acid monomers exhibit three conformational isomers: cis–cis, cis–trans, and trans–trans.
At low temperature and atmospheric pressure, solid carbonic acid is amorphous and lacks Bragg peaks in X-ray diffraction.
But at high pressure, carbonic acid crystallizes, and modern analytical spectroscopy can measure its geometry.

Uses Of Carbonic acid:
Carbonic acid is used in the manufacture of soft drinks, inexpensive and artificially carbonated sparkling wines, and other bubbly drinks.
Carbonic acid (H2CO3) is produced by dissolving carbon dioxide in water. When formed under pressure, it is the gas used in carbonated drinks. 
In nature, it dissolves the limestone in caves, resulting in the formation of stalactites and stalagmites. 

Carbonic acid is corrosive as are other acids, although it is considered a rather weak acid.
Carbonic acid is widely used in the food and beverage industry, where it is responsible for the acidity and effervescence of carbonated drinks.
It provides a mild acidic taste and contributes to microbial stability without the need for strong mineral acids.

This makes it suitable for soft drinks, sparkling water, and beer carbonation.
In water treatment and desalination systems, carbonic acid is used for pH adjustment and alkalinity control.
Carbonic acid is generated in situ by dissolving carbon dioxide, allowing safer and more controllable acidification compared to strong acids.

This approach helps prevent scaling and improves the efficiency of treatment processes.
Carbonic acid is used in industrial cleaning and metal processing to remove carbonate scales and mineral deposits.
It is particularly effective in dissolving calcium carbonate without causing severe corrosion to equipment.

As a result, it is applied in boiler maintenance, heat exchangers, and cooling systems.
In agriculture, carbonic acid plays a role in soil chemistry and nutrient availability.
Carbonic acid enhances the solubility of certain minerals, making nutrients more accessible to plant roots.

This process supports root respiration and overall soil fertility.
Carbonic acid is also relevant in carbon capture and storage technologies.
Carbonic acid forms as an intermediate when carbon dioxide is absorbed into aqueous solutions.

Understanding its behavior helps optimize CO₂ sequestration and emission-reduction systems.
Carbonic acid is used in controlled carbonation processes in the pharmaceutical and food industries to regulate pH without introducing persistent acid residues.
Because it decomposes into CO₂ and water, it allows temporary acidification that can be easily reversed.

This property is useful in effervescent formulations and buffered liquid products.
In enhanced oil recovery and subsurface engineering, carbonic acid is applied to modify rock–fluid interactions.
Injection of CO₂-rich water forms carbonic acid, which increases carbonate rock permeability by partial dissolution.

This improves fluid flow in reservoirs and enhances hydrocarbon recovery efficiency.
Carbonic acid is utilized in laboratory and analytical chemistry as a mild acid source.
It is often generated in situ for studying carbonate equilibria and buffering behavior.

This allows precise investigation of pH-dependent reactions without adding strong acids.
In aquaculture and aquatic system management, carbonic acid is used to control pH and dissolved CO₂ levels.
Maintaining proper carbonic acid–bicarbonate balance is essential for fish respiration and shell-forming organisms.

Careful regulation helps prevent stress and metabolic imbalance in aquatic species.
Carbonic acid is also applied in environmental remediation processes.

Carbonic acid is used to mobilize carbonate-bound contaminants in soils and sediments during controlled extraction treatments.
This approach enables cleaner remediation with reduced chemical residue compared to stronger acids.

Safety Profile Of Carbonic acid:
Carbonic acid is generally considered a low-hazard substance because it is weak and decomposes readily into carbon dioxide and water.
However, in concentrated or pressurized systems, it can still cause irritation to the eyes, skin, and mucous membranes.
Direct contact with acidic solutions may result in mild redness or discomfort.

Inhalation of high concentrations of carbon dioxide associated with carbonic acid formation poses a significant hazard.
Elevated CO₂ levels can displace oxygen in confined spaces, leading to dizziness, shortness of breath, headache, or loss of consciousness.
This risk is particularly relevant in industrial carbonation, fermentation, and carbon capture facilities.

Carbonic acid can contribute to corrosion of metals, especially carbon steel and iron, in aqueous CO₂ environments.
This corrosion can weaken pipelines, storage tanks, and industrial equipment if not properly controlled.
Such damage may lead to leaks, structural failure, and secondary safety hazards.

In aquatic environments, excessive carbonic acid formation can lower pH and stress living organisms.
Carbonic acid acidification can impair shell formation in mollusks and corals by reducing carbonate availability.
This ecological hazard is a major concern in ocean acidification scenarios.