Who discovered carbon dioxide (CO₂)?

Carbon dioxide (CO₂) is a colorless, odorless gas that is essential in chemistry, biology, and environmental science. It is produced naturally in processes like respiration, combustion, and decomposition, and it is also used in industries for carbonated drinks, fire extinguishers, and as a refrigerant.

The discovery of carbon dioxide is credited to Joseph Black, a Scottish chemist, in the 18th century. Black observed that a certain gas was released when lime (calcium carbonate) was heated, or when acid reacted with carbonate compounds. He called this gas “fixed air”, which we now know as carbon dioxide. Black’s experiments demonstrated that this gas was denser than air, did not support combustion, and was distinct from ordinary atmospheric air. His discovery laid the foundation for understanding chemical reactions involving gases and inspired further research by scientists like Lavoisier, who later named it carbon dioxide.

Carbon dioxide plays a critical role in the carbon cycle, where it is absorbed by plants during photosynthesis to produce oxygen and glucose. It is also a major greenhouse gas, trapping heat in the Earth’s atmosphere and influencing climate patterns. In chemical terms, CO₂ reacts with water to form carbonic acid (H₂CO₃), which is important in ocean chemistry and acid-base reactions.

Understanding the history of CO₂ helps students appreciate the development of modern chemistry, experimental methods, and the significance of careful observation in scientific discoveries. Joseph Black’s meticulous experiments are an early example of the scientific method applied to gases and chemical reactions.