Which gas is typically associated with the acidity of a solution?

Carbon Dioxide is the gas commonly associated with the acidity of a solution for several reasons. When carbon dioxide (CO2) dissolves in water, it undergoes a chemical reaction that forms carbonic acid (H2CO3). This weak acid can dissociate into bicarbonate (HCO3^-) and hydrogen ions (H+), which directly contribute to increased acidity. The presence of these hydrogen ions lowers the pH of the solution, making it more acidic.

In natural environments, this process plays a significant role in the acidification of oceans and lakes, impacting ecosystems and aquatic life. Therefore, the relationship between carbon dioxide and acidity in solutions is crucial to both chemistry and environmental science.