Without doubt the grandfather of home cleaning myths is the notion that mixing bicarb and vinegar together makes an effective cleaning mixture.
It won’t. Anything this mixture cleans will be cleaned just as effectively with water.
But why do people think it DOES clean? The reason simply is that it FOAMS and people associate foaming with cleaning. That’s it.
In this case, the foam is not soap bubbles, it’s carbon dioxide formed by the reaction of acetic acid with sodium hydrogen carbonate:
NaHCO3 + CH3COOH → NaCH3COO + CO2↑ + H2O
The ↑ next to the CO2 indicates that it is a gas.
So you mix acetic acid with sodium hydrogen carbonate, and the reaction products are sodium acetate, carbon dioxide, and water.
Now none of those reaction products have any cleaning properties. The only things in the whole brew with any cleaning properties are the reactants – bicarb and vinegar. Bicarb is mildly alkaline and is therefore mildly caustic and can therefore can be useful where organic matter is involved, although anything that bicarb will clean, it’s more alkaline bigger brother (Sugar Soap) will do better.
Vinegar (acetic acid) is also not without its charms as a cleaner. It’s a weak acid, along with several other weak acids that find their way into cleaning products (mostly bathroom cleaners) such as formic, citric, and sulfamic. It is a weaker acid than these three and so will not do as good a job under the same circumstances.
But, of course, when you mix the acid and alkali together, each neutralises the other and these residual cleaning properties are removed. The only cleaning power a mixture of these two chemical will produce is when one is present in excess. That is, if you have more bicarb than acid, you’ll get some of the cleaning properties of the bicarb. If you have an excess of the acid, you will have some of the residual properties of the acid.
Also, people seem to like using these chemicals as they somehow think they are natural. They aren’t. Bicarb soda is made in a chemical factory by a process called The Solvay Process. Vinegar is made from petroleum. Ethane is oxidised first to acetic anhydride, and then onto acetic acid. An alternative process for the manufacture of vinegar is by natural fermentation of natural sugars (such as apple cider vinegar). This is natural, but is not the stuff in the White Vinegar that most people use to clean.
So the bottom line is this. Mixing bicarb soda and vinegar is nothing more than mixing together two synthetically-made chemicals to make bubbles, with any cleaning properties residing wholly in the mind of the user.