Vinegar and baking soda are common items found in the kitchen. Many of us have mixed them together in childhood experiments, creating fizzy volcanoes and geysers.
However, people also often combine vinegar and baking soda to make a supposedly effective household cleaner. Unfortunately, the chemical reaction behind the fizz doesn’t really support the cleaning claims. The fizzy reaction is essentially a visual “placebo” effect, resulting from the combination of an acid and a base.
So, how does this reaction work, and is it really worth using these substances for cleaning purposes? To understand this better, it’s helpful to have a basic understanding of chemistry.
What’s an acid?
Foods with a sour taste typically contain acids. Examples include citric acid in lemon juice, malic acid in apples, lactic acid in yoghurt, and phosphoric acid in soft drinks. Most vinegars contain approximately 4–10% acetic acid, along with water and small amounts of flavor compounds.
There are other naturally occurring acids, such as formic acid from ant bites and hydrochloric acid in our stomachs. Industrially, sulfuric acid is used in mineral processing, nitric acid in fertilizer production, and highly potent hydrofluoric acid is used for glass etching.
All these acids share similar properties. They can release positively charged hydrogen ions into water and, depending on their strength, can dissolve minerals and metals through various chemical reactions.
This is why vinegar is effective for cleaning showers or kettles, as it can react with and dissolve mineral deposits like limescale.
Other common acidic cleaning agents include oxalic acid for revitalizing timber decks, hydrochloric acid in concrete cleaners, and sulfamic acid in strong toilet cleaners.
Adding some vinegar to your shower cleaning routine can help to dissolve away the limescale deposits on the glass. Source: The Conversation / Karolina Grabowska/Pexels
What’s a base?
In chemistry, bases – the opposite of acids in many ways – can bind hydrogen ions instead of releasing them. This property helps in lifting and dissolving insoluble grime in water, as well as breaking down fat molecules.
Baking soda (also known as sodium hydrogen carbonate, sodium bicarbonate, or bicarb) is a relatively weak base. Stronger common bases include sodium carbonate (washing soda), sodium hydroxide (lye), and ammonia.
Sodium hydroxide is a powerful drain cleaner due to its ability to dissolve fats and hair, allowing blockages to be easily cleared.
Mixing a base and an acid
Combining vinegar and baking soda results in an immediate chemical reaction, producing water, sodium acetate (a salt), and carbon dioxide – the fizzing part.
The amount of carbon dioxide gas released from baking soda is significant – just one tablespoon can release over five liters of gas! However, this only happens when enough acid is added.
In chemical reactions, equal amounts of reagents are typically used. A perfect balance of acetic acid and baking soda would yield water, carbon dioxide, and sodium acetate. However, many vinegar and bicarbonate cleaner recipes use an excess of one component over the other. For example, a DIY oven cleaner from TikTok calls for one and a half cups of baking soda and one-quarter cup of vinegar.
Calculating the chemical reaction reveals that after the fizzing stops, over 99% of the added baking soda remains. Therefore, the active cleaning agent here is actually the baking soda (along with the scrubbing action).
Ovens can be more effectively cleaned with stronger, sodium hydroxide-based cleaners (although these are also more caustic). Many modern ovens also have a self-cleaning feature, so it’s advisable to check your product manual before using any chemical cleaners.
What about the sodium acetate?
Enthusiasts of vinegar and baking soda mixtures might wonder if the resultant sodium acetate is the secret cleaning agent. However, sodium acetate is actually a weaker base than baking soda, so it doesn’t contribute much to cleaning the surface being scrubbed.
Sodium acetate is commonly used in crystallization-based heating packs and as a concrete sealant, but not typically as a cleaner.
Sorry to burst your bubbles
In some rare cases, mixing vinegar and baking soda may be helpful for cleaning, especially when the fizzing has a mechanical effect like in a blocked drain. However, in most cases, it’s better to use either vinegar or baking soda alone, depending on the cleaning task at hand. It may not be as visually exciting, but it will likely be more effective.
Lastly, remember that mixing cleaning chemicals at home can be risky. Always read the product label and instructions before attempting any DIY mixtures. For added safety, refer to the product’s safety data sheet for more information.
Nathan Kilah is a senior lecturer in chemistry at the University of Tasmania.
