Why is carbon dioxide produced in neutralization reaction?

Carbon dioxide is produced in a neutralization reaction when an acid reacts with a carbonate or bicarbonate base. During this process, the acid donates protons (H⁺ ions), which react with the carbonate (CO₃²⁻) or bicarbonate (HCO₃⁻) ions to produce carbonic acid (H₂CO₃). This carbonic acid is unstable and quickly decomposes into water (H₂O) and carbon dioxide (CO₂), which is released as a gas. Thus, the formation of CO₂ is a characteristic outcome when carbonates or bicarbonates are involved in acid-base neutralization.