The pH Scale: Using it to Choose the Right Cleaning Chemical

by Mike Besley on 23-9-2016


You learnt about the pH scale at school all those years ago, and you probably listened with half an ear, right?

Well, you need to know about it because it applies when you are choosing a chemical to clean with.  This knowledge will keep you safe, but also how effective the product will be to use.

The Science Bit - What Does it Mean?


The ‘pH’ bit is an abbreviation of ‘potential of hydrogen’, and the numbers on the scale represent the concentration of hydrogen ions in a water-based solution. A high pH is a higher concentration, and a low pH scale is a lower concentration, or even an absence of hydrogen altogether.


Running from 0-14, the pH scale can help you to determine whether a substance is acidic or alkaline. A substance with a pH of 7 is neutral; anything lower than 7 is increasingly acidic, with 0 being the most acidic, and anything higher than 7 is increasingly alkaline, with 14 being the most alkaline.  In a neutral solution you have both acidic and alkaline elements but they are equal making the product neutral.


Next, there is one other factor relative to pH that needs to be explained, and has to do with the corrosiveness of a compound. Both acids and alkali’s have the capability of being corrosive, to classify a product or compound as being corrosive means that it would have the potential to eat away at something, in some cases very rapidly, and it would have the capability of being harmful to human tissue as well as inanimate objects.


It is important that every one who uses cleaning chemicals understands that some compounds are corrosive by their very nature and should be handled according to the label directions on the container.  Any corrosive chemical will have the corrosive symbol on the container


CorrosiveAll corrosive products are labeled as such and must follow strict guidelines. 

This also shows that the incorrect use of chemicals can damage surfaces when cleaning.


When you understand the proper use of cleaning chemicals, it becomes increasing clear that knowing about pH is pretty important!


How Does the pH Scale Relate To Cleaning Chemicals?


When cleaning a substance off a hard surface or a carpet, your goal is to neutralize the soil’s acidic or alkaline ions. Acid neutralizes alkaline, and alkaline neutralizes acid. Therefore, contrary to the myth that a higher pH level makes the best cleaning product, the following is actually true:  


  • To clean acidic soils, you want a cleaning product that falls in the alkaline spectrum (pH greater than 7)


  • To clean alkaline soils, you want a cleaning product that falls in the acidic spectrum (pH less than 7)


For acid-based soils, such as those listed below, use alkali cleaners.

  •  Greasy floors
  • Dirty walls
  • Cigarette tars
  • Engines and tools
  • Motor oils, diesel oil, axle grease
  • Cooking oil
  • Ventilation hoods
  • Ovens

 For alkaline-based soils, such as those listed below, use acid cleaners.

  •  Water spots
  • Rust
  • Calcium deposits
  • Lime deposits
  • Inside the dishwasher
  • Toilet bowls
  • Shower stalls
  • Urinals


Knowledge is Power When it Comes to Effective Cleaning.


Th pH scale is always marked on a coshh sheet and often on the label of products and you should check this before using.


It is therefore essential that the correct product is selected for the task at hand and it is correctly diluted.  If you are still confused or would like further help, why not take our online Coshh training course by clicking on the link below or ask us to help you audit the products you should be using to be safe.

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