Yes, CO2 (Carbon dioxide) is soluble in water. 1 It is soluble in water because CO2 molecules can react with water molecules to form carbonic acid (H2CO3), which then dissociates into bicarbonate ions [(HCO3)-] and hydrogen ions (H+), allowing for its dissolution in water.
Well, this was just a simple answer. But there are few more things to know about this topic which will make your concept super clear.
So let’s dive right into it.
Key Takeaways: Is CO2 Soluble in Water?
- CO2 is soluble in water due to its polarity and the formation of carbonic acid when it reacts with water.
- Factors such as temperature, pressure, pH, salinity, and the presence of other solutes can influence the solubility of CO2 in water.
- Nonpolar solvents like hexane, heptane, and benzene have low solubility for CO2 compared to polar solvents like water. 2
Explanation: Why is CO2 soluble in water?
Carbon dioxide (CO2) is soluble in water due to its molecular properties and the nature of intermolecular forces involved.
When CO2 dissolves in water, it undergoes a reaction called hydration, resulting in the formation of carbonic acid (H2CO3): 3
CO2 + H2O → H2CO3
The solubility of CO2 in water can be attributed to several factors:
- Hydrogen bonding: Water molecules can form hydrogen bonds with each other due to the presence of hydrogen atoms with a partial positive charge and oxygen atoms with a partial negative charge. 4 When CO2 dissolves in water, it can disrupt some of these hydrogen bonds, allowing water molecules to interact with CO2 molecules through weaker intermolecular forces.
- Dipole-dipole interactions: The polar nature of water and polar bonds of carbon dioxide allows for dipole-dipole interactions between the positively charged hydrogen atoms of water and the negatively charged oxygen atom of CO2. These interactions contribute to the solubility of CO2 in water.
It is important to note that while CO2 is soluble in water, its solubility is relatively low compared to some other gases. Factors such as temperature, pressure, and the presence of other solutes can influence the solubility of CO2 in water. 5
What factors affect the solubility of CO2 in water?
The solubility of carbon dioxide (CO2) in water can be influenced by several factors:
- Temperature: Generally, the solubility of gases in water decreases as temperature increases. 6 This means that at higher temperatures, less CO2 can dissolve in water. Conversely, at lower temperatures, the solubility of CO2 increases. This relationship follows Henry’s Law, which states that the solubility of a gas in a liquid is directly proportional to the partial pressure of the gas above the liquid.
- Pressure: Increasing the pressure of CO2 above the water can enhance its solubility. 7 According to Henry’s Law, the solubility of a gas in a liquid is directly proportional to the partial pressure of the gas. Therefore, higher pressures of CO2 will lead to greater solubility in water. This is the principle behind carbonation in carbonated beverages, where high-pressure CO2 is dissolved in the liquid.
- pH: The pH of water can influence the solubility of CO2 because CO2 reacts with water to form carbonic acid (H2CO3). Carbonic acid can dissociate into hydrogen ions (H+) and bicarbonate ions (HCO3)-. In more acidic conditions (lower pH), the equilibrium shifts towards the formation of more CO2 molecules. Therefore, lower pH values can increase the solubility of CO2 in water.
- Presence of other solutes: The presence of other solutes in water can influence the solubility of CO2. 8 For example, the presence of dissolved organic compounds or other gases can compete for interactions with water molecules, potentially affecting the solubility of CO2.
It is important to note that these factors can interact with each other, and the solubility of CO2 in water is a complex equilibrium process that depends on multiple variables.
Further reading
Why is NH3 (Ammonia) Soluble in Water?
Why is Methanol (CH3OH) Soluble in Water?
Why is Acetone Soluble in Water?
Is Hexane Soluble in Water?
Why is Ethanol Soluble in Water?
Jay is an educator and has helped more than 100,000 students in their studies by providing simple and easy explanations on different science-related topics. He is a founder of Pediabay and is passionate about helping students through his easily digestible explanations.
Read more about our Editorial process.
References
- CHEMICAL FEATURES OF WATER. (n.d.). CHEMICAL FEATURES OF WATER. https://www.fao.org/3/ac183e/AC183E06.htm
- Lay, E. N., Taghikhani, V., & Ghotbi, C. (2006, September 16). Measurement and Correlation of CO2 Solubility in the Systems of CO2 + Toluene, CO2 + Benzene, and CO2 + n-Hexane at Near-Critical and Supercritical Conditions. Journal of Chemical & Engineering Data, 51(6), 2197–2200. https://doi.org/10.1021/je0602972
- Wang, H., Zeuschner, J., Eremets, M., Troyan, I., & Willams, J. (2016, January 27). Stable solid and aqueous H2CO3 from CO2 and H2O at high pressure and high temperature. Scientific Reports, 6(1). https://doi.org/10.1038/srep19902
- Hydrogen bonds in water (article) | Khan Academy. (n.d.). Khan Academy. https://www.khanacademy.org/science/ap-biology/chemistry-of-life/structure-of-water-and-hydrogen-bonding/a/hydrogen-bonding-in-water
- Solubility and Factors Affecting Solubility. (2013, October 2). Chemistry LibreTexts. https://chem.libretexts.org/Bookshelves/Physical_and_Theoretical_Chemistry_Textbook_Maps/Supplemental_Modules_(Physical_and_Theoretical_Chemistry)/Equilibria/Solubilty/Solubility_and_Factors_Affecting_Solubility
- Solubility. (n.d.). Solubility. https://www.chem.fsu.edu/chemlab/chm1046course/solubility.html
- 13.4: Effects of Temperature and Pressure on Solubility. (2013, November 24). Chemistry LibreTexts. https://chem.libretexts.org/Bookshelves/General_Chemistry/Book%3A_General_Chemistry%3A_Principles_Patterns_and_Applications_(Averill)/13%3A_Solutions/13.04%3A_Effects_of_Temperature_and_Pressure_on_Solubility
- Solubility – Wikipedia. (2015, April 22). Solubility – Wikipedia. https://en.wikipedia.org/wiki/Solubility
