Equation for the Reaction Between Baking Soda and Vinegar

The reaction between baking soda (sodium bicarbonate) and vinegar (dilute acetic acid) generates carbon dioxide gas, which is used in chemical volcanoes and other projects. Here is a look at the reaction between baking soda and vinegar and the equation for the reaction.

How the Reaction Works

The reaction between baking soda and vinegar actually occurs in two steps, but the overall process can be summarized by the following word equation: baking soda (sodium bicarbonate) plus vinegar (acetic acid) yields carbon dioxide plus water plus sodium ion plus acetate ion

The chemical equation for the overall reaction is:

NaHCO₃(s) + CH₃COOH(l) → CO₂(g) + H₂O(l) + Na⁺(aq) + CH₃COO^-(aq)

with s = solid, l = liquid, g = gas, aq = aqueous or in water solution

Another common way to write this reaction is:

NaHCO₃ + HC₂H₃O₂ → NaC₂H₃O₂ + H₂O + CO₂

The above reaction, while technically correct, does not account for the dissociation of the sodium acetate in water.

The chemical reaction actually occurs in two steps. First, there is a double displacement reaction in which acetic acid in the vinegar reacts with sodium bicarbonate to form sodium acetate and carbonic acid:

NaHCO₃ + HC₂H₃O₂ → NaC₂H₃O₂ + H₂CO₃

Carbonic acid is unstable and undergoes a decomposition reaction to produce the carbon dioxide gas:

H₂CO₃ → H₂O + CO₂

The carbon dioxide escapes the solution as bubbles. The bubbles are heavier than air, so the carbon dioxide collects at the surface of the container or overflows it. In a baking soda volcano, detergent usually is added to collect the gas and form bubbles that flow somewhat like lava down the side of the 'volcano.' A dilute sodium acetate solution remains after the reaction. If the water is boiled off of this solution, a supersaturated solution of sodium acetate forms. This "hot ice" will spontaneously crystallize, releasing heat and forming a solid that resembles water ice.

The carbon dioxide released by the baking soda and vinegar reaction has other uses besides making a chemical volcano. It can be collected and used as a simple chemical fire extinguisher. Because carbon dioxide is heavier than air, it displaces it. This starves a fire of the oxygen needed for combustion.