Chemical Equation for Baking Soda and Vinegar Reaction

The baking soda and vinegar chemical reaction finds use in chemical volcanoes, carbon dioxide production, and sodium acetate (hot ice) synthesis. It’s an aqueous (water-based) reaction between sodium bicarbonate and the acetic acid from vinegar. Here is the balanced chemical equation for the reaction and a closer look at the steps involved.

Balanced Chemical Equation for Baking Soda and Vinegar Reaction

One mole of sodium bicarbonate (baking soda) reacts with one mole of acetic acid (from vinegar) to yield one mole of sodium acetate, one mole of water, and one mole of carbon dioxide. The balanced chemical equation is:

NaHCO₃ + HC₂H₃O₂ → NaC₂H₃O₂ + H₂O + CO₂

But, sodium acetate dissociates into its ions, so a better way to write the reaction is:

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

Here, NaHCO₃ is sodium bicarbonate, CH₃COOH is acetic acid, CO₂ is carbon dioxide, H₂O is water, Na⁺ is the sodium cation, and CH₃COO^– is the acetate anion. Also, s = solid, l = liquid, g = gas, aq = aqueous or in water solution.

How the Reaction Works

Remember, this chemical reaction takes place in water, so sodium bicarbonate and acetic acid dissociate into their ions, so the ions can essentially “switch partners” to form new products:

NaHCO₃(aq) + HC₂H₃O₂(aq) = Na⁺(aq) + HCO^–₃(aq) + H⁺(aq) + C₂H₃O₂^–(aq)

The baking soda and vinegar reaction actually proceeds in two steps. First, sodium bicarbonate reacts with acetic reaction in a double displacement reaction to form sodium acetate and carbonic acid. Because baking soda is a base and acetic acid is an acid, the reaction is also an example of an acid-base neutralization reaction. The reason this happens at all is because the products are more thermodynamically stable than the reactants:

NaHCO₃ + HC₂H₃O₂ → NaC₂H₃O₂ + H₂CO₃

Carbonic acid is unstable, so it rapidly undergoes a decomposition reaction to form water and carbon dioxide:

H₂CO₃ → H₂O + CO₂

Because the reaction occurs in water and sodium acetate is soluble in water, the chemical dissociates into sodium ions and acetate ions. If you boil off or evaporate all the water, you’ll get solid sodium acetate. Sodium acetate is called “hot ice” because a supersaturated solution spontaneously crystallizes, releasing heat and forming a crystalline solid that looks like water ice.

The carbon dioxide formed in the reaction escapes as bubbles of carbon dioxide gas. A small amount of detergent added to a baking soda and vinegar volcano traps the carbon dioxide gas to make “lava” bubbles that flow down the side of the container.

Safety

The baking soda and vinegar reaction is among the safety chemical reactions for children because both the reactants and products are safe enough to eat! The only consideration is that carbon dioxide released by the reaction is heavier than air and sinks to the bottom of the room. If the reaction is performed on a very large scale, enough carbon dioxide gas might be produced to cause hypoxic conditions near the floor. It’s unlikely anyone would mix enough chemicals for this to happen, but if you plan on filling your kiddie pool with baking soda and vinegar, do it outdoors on a breezy day 🙂

References

• Clayden, Jonathan; Greeves, Nick; Warren, Stuart; Wothers, Peter (2001). Organic Chemistry (1st ed.). Oxford University Press. ISBN 978-0-19-850346-0.
• Seidell, Atherton; Linke, William F. (1952). Solubilities of Inorganic and Organic Compounds. Van Nostrand.