pH in cleaning
Why the acid or alkali choice decides both what a cleaner removes and what it damages. The two are the same property seen from opposite sides.
In detail
pH measures how acidic or alkaline a solution is, and in cleaning it is the single most useful predictor of what a product will do. Acids dissolve mineral deposits: they react with carbonates, which is what removes limescale, and they help with rust and some metal staining. Alkalis attack organic soil: they break down fats into soaps and hydrolyse proteins, which is what makes them effective on grease and food residue. Because the mechanisms are chemical reactions with the soil, they are also chemical reactions with anything else made of the same stuff. An acid that dissolves carbonate scale dissolves carbonate stone. An alkali that hydrolyses a protein stain hydrolyses a wool fibre. This symmetry is the most reliable rule of thumb in the subject: the more strongly acidic or alkaline a cleaner is, the more effective it is on its target soil and the narrower the range of surfaces it can safely touch. A near-neutral surfactant cleaner sits at the other end — less potent, and safe on far more.
Why
- Grout is explained by pH in cleaning
- Citric acid is explained by pH in cleaning
- Acetic acid (vinegar) is explained by pH in cleaning
- Descaling is explained by pH in cleaning
- Wood ash is explained by pH in cleaning
- Sodium carbonate is explained by pH in cleaning
A considerably stronger alkali than bicarbonate, and the strength is both what it is for and what restricts it.
- Sodium hydroxide is explained by pH in cleaning
- Sodium bicarbonate is explained by pH in cleaning
The weaker half of a pair that is always described together.
- Oxalic acid is explained by pH in cleaning
- Phosphoric acid is explained by pH in cleaning
- Hydrochloric acid is explained by pH in cleaning
- Sulphuric acid is explained by pH in cleaning
- Potassium hydroxide is explained by pH in cleaning
- Trisodium phosphate is explained by pH in cleaning
- Borax is explained by pH in cleaning
- Descaler is explained by pH in cleaning
- Dishwasher detergent is explained by pH in cleaning
- Drain cleaner is explained by pH in cleaning
- Neutral cleaning is explained by pH in cleaning
- Ammonia is explained by pH in cleaning
- Quicklime is explained by pH in cleaning
- Sugar soap is explained by pH in cleaning
- Floor cleaner is explained by pH in cleaning
- Amphoteric surfactant is explained by pH in cleaning
Sources for this page
Sources
Cleaning product science and ingredient information
American Cleaning Institute (ACI) · Trade or professional body
Relied on for: That cleaning products are formulated across a pH range according to the soil type targeted.
Kirk-Othmer Encyclopedia of Chemical Technology
John Wiley & Sons · Reference work
Relied on for: That alkaline hydrolysis acts on fats and proteins, and that acids react with carbonates to form soluble salts.