pH of Some Common Products Unveiled
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FUNX650
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•A little something extra:
-hydration enthalpy
-solutions having infinite dilution
Bob
allenk4
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Just trying to understand
Part of that process is asking questions as an indication to the teacher that you have a knowledge gap to fill
It is important to remember that pH is not measuring acidity or alkalinity. pH is a measure of the concentration of hydrogen ions, specifically in an aqueous solution (i.e. it doesn't apply to non-aqueous products, for instance, gasoline does not have a pH). So a change of one pH unit refers to a factor of 10 change in the concentration of hydrogen ions. The terms acidity and alkalinity are vague descriptions and there are many other factors which are important, very notably the 'strength' of the acid/base (which defines how completely it dissociates).
swanicyouth
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swanicyouth
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To my friend Bunky, who is always a gentleman...
1.5oz : ~ 4 gallons - 100% neutral.
Still convinced all soaps will be neutral at their dilution and "pH neutral soap" is complete marketing gimmickry.
Again, it depends entirely upon the use of the term 'soap'. In the UK, the term 'shampoo' is used and you would be spot on the money, all shampoos should be pH neutral when diluted (if they are not, they should not be sold as a shampoo).
WRAPT C5Z06
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I remember you saying that AF Avalanche has a pH of ~13 and is caustic. In this test, it shows only 10 neat, which isn't very alkaline. When you dilute it, the pH may drop more. I'm not sure Avalanche is as caustic as you might have thought?
I suspect the reality is different again - word on the grapevine is that AF went through a number of different manufacturers a while back (they may be settled now). The original formulations did not belong to AF (as is commonly the case with detailing brands) so it is highly likely that the products have changed during their lifetime. If the pH is now only 10, the product differs dramatically from the version I tested so it is highly unlikely to be caustic. I only wish that AF were a little bit more forthcoming about all this kind of thing.
WRAPT C5Z06
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rops:
WRAPT C5Z06
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So, a soap with a pH of 8 with high detergent is going to be more harsh than a soap with a pH of 11 with low detergent?
swanicyouth
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Technically you are probably right, but it's really semantics. Dilution of an acid with water will bring it closer to it's neutral state (pH 7) which could be construed as "neutralizing".
FUNX650
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I was under the impression that at least for certain acids, such as "weak" acids---that undergo incomplete disassociation, become stronger as they are diluted.
I would think that, with this diluted "weak acid" being a now stronger "weak acid", it would relate to it also having a lower pH---that is: not being/going closer to "neutral".
Of course, I could be way off course.
Any and all corrections to the above are appreciated.
Bob
SYMAWD
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Adding water to a weak acid will still raise the pH because there will be less free H+ in the solution.
I am going to assume that Dr G is being taking out of context, somewhat. Yes, there are a load of other things in there and yes this would not be far from the truth when it comes to car shampoos - nearly neutral cleaners for heavy dilution and use by hand. In this product type, the variation of pH is going to be minimal and there is not a large difference in the cleaning power with a couple of pH points. However, this generalisation is NOT correct for other product types. I would go as far as saying that pH is the key component to many formulations, the other ingredients are there to allow the pH to do its work. This is the reason why, for example, APCs and heavy duty cleaners tend to have high pH - there is simply no economical way to achieve the same cleaning power.
Actually, there will be more free hydrogen ions.... if you want to be accurate, pH measures the concentration of hydrogen ions. It is an inverse log so if you reduce the concentration, the pH increases and vice versa. So if you add water (mid concentration), to acid (high concentration), the concentration goes down and the pH goes up. When talking about weak acids/bases, buffering is more of a possibility with other ingredients. What can happen is that the change in
hydrogen ion concentration can lead to a dissociation of the buffering component which then effectively counteracts the change in hydrogen concentration.
Really, way beyond the scope of a forum like this and I don't really see any benefit in a detailer knowing this stuff.
swanicyouth
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Here is another one folks. Sonax Gloss Shampoo.
Another awesome product that never gets mentioned. I like this because unlike most regular soaps, it actually makes the solution feel slick and it smells like lemons.
pH neutral (correct dilution - 2 caps : ~ 4.5 gallons):
Another awesome product that never gets mentioned. I like this because unlike most regular soaps, it actually makes the solution feel slick and it smells like lemons.
pH neutral (correct dilution - 2 caps : ~ 4.5 gallons):
swanicyouth
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While I'm at it... 1Z ColourTec Wheel Rim Cleaner.
pH ~ 8 (pretty close to neutral)
pH ~ 8 (pretty close to neutral)
swanicyouth
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Ok. Now I'm just bumping my own thread...
pH ~ 12
pH ~ 12