What gas is formed when you mix water and baking soda?

When water is mixed with baking soda (sodium bicarbonate), a chemical reaction takes place, resulting in the formation of several products, including carbon dioxide gas (CO2). The chemical equation for this reaction is:

NaHCO3 (sodium bicarbonate) + H2O (water) → CO2 (carbon dioxide) + H2O (water) + Na+ (sodium ion)

The carbon dioxide gas produced during this reaction causes the characteristic fizzing and bubbling effect when baking soda is added to water. This gas is responsible for creating the leavening effect in baking, causing baked goods to rise. Additionally, the sodium ions released in the reaction can contribute to the alkaline taste associated with baking soda.