and Why is a pH test generally not run on lubricating oils?
What is pH?
- Thread starter BOBISTHEOILGUY
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Bob,
1. The PH is a measurement of the acidity or Alkalinity of an aqueous solution.
2. We do measure TAN in Oils but this only gives us the amount of concentration of acid in the oil, not the strength of the acid present.
There isn't an acceptable/standarized PH test on oil, as we would have to seperate the acid to measure strength.
1. The PH is a measurement of the acidity or Alkalinity of an aqueous solution.
2. We do measure TAN in Oils but this only gives us the amount of concentration of acid in the oil, not the strength of the acid present.
There isn't an acceptable/standarized PH test on oil, as we would have to seperate the acid to measure strength.
The given answer to this question is..
pH measures the acidity of alkalinity of an aqueous solution. Since oil and water don't mix, pH values for oil are not accurate.
pH measures the acidity of alkalinity of an aqueous solution. Since oil and water don't mix, pH values for oil are not accurate.
Sorry, not trying to upset you, but the "p" in pH does not mean potential.
It actually just means "-log" So, pH is just the negative log of "H." Well, what is this H? Well, it represents the hydronium ion concentration in the solution (the hydronium ion is denoted H30+ or sometimes as a shorthand, H+) . So, if you know the hydronium ion concentration, you know the pH!! And vice versa.
For example, if we have a hydronium ion concentration of 1.0x10-7M, we would have a pH of 7. We use pH because it is shorter than 1.0x10-7M........chemists are lazy!!
Hope this helps.....
For example, if we have a hydronium ion concentration of 1.0x10-7M, we would have a pH of 7. We use pH because it is shorter than 1.0x10-7M........chemists are lazy!!
Hope this helps.....
Turbochem – good explanation. You are right Chemists are lazy!! Somehow I think it’s easy to demonstrate the meaning of such things when round pH numbers AREN’T used. For example:
pH=3.7 = -log[H30+]
-3.7= log[H30+]
-4.0+0.3=log[H30+]
1.0x10(-4) x 1.0x10(0.3)= [H30+]
2X10 (-4) = [H30+]
So a pH of 3.7 = 2 X10 (-4)M hydronium ion concentration.
I do, however, think the p = potenz, a German word.
pH=3.7 = -log[H30+]
-3.7= log[H30+]
-4.0+0.3=log[H30+]
1.0x10(-4) x 1.0x10(0.3)= [H30+]
2X10 (-4) = [H30+]
So a pH of 3.7 = 2 X10 (-4)M hydronium ion concentration.
I do, however, think the p = potenz, a German word.
Bring back litmus paper! Pink...or blue? That's the question!
[ January 07, 2003, 12:58 PM: Message edited by: 68redlines73 ]
[ January 07, 2003, 12:58 PM: Message edited by: 68redlines73 ]
Ah...my days in the lab...so very long ago...
Hey,I was taught that pH meant 'power of Hydrogen'. I used to work with 37% formaldehyde; nasty stuff!
"The concentration of hydrogen ions in aqueous solutions range from about 1 molar in 1 N HCl to about 10exp(-14) molar in 1 N NaOH. Because of this wide range of concentrations Sorenson adopted an exponential notation in 1909. He defined pH as the negative exponent of 10 which gives the hydrogen ion concentration.
pH = -log (H+)"
Physical chemistry, third edition, Farrington Daniels and Robert A. Alberty pp 262, 263.
Now, for the non-aqueous chemistry, there are some IUPAC methods to measure pH, take a look at this reference: http://books.google.com/books?id=ieUi_y0...nts&f=false
I am not sure to understand at all, it is really difficult for me to extend or accept the pH definition to substances as lubricants (Mineral or PAOs based, and yes, some basestocks from the V group). I think that somehow i can't leave behind the basic definition stated by Sorenson.
Once i had a really bitter argument (5 years ago, as a matter of fact) with a boss when i refused to sign a pH lubricant QC report based on the color of a pH strip.
"pH measures the acidity of alkalinity of an aqueous solution. Since oil and water don't mix, pH values for oil are not accurate."
Has this argument been changed in a significative way?
In practical terms, the pH measure in lubricants is irrelevant or useless?
By the way, can't remember any ASTM test related exclusively to pH. Are there?
pH = -log (H+)"
Physical chemistry, third edition, Farrington Daniels and Robert A. Alberty pp 262, 263.
Now, for the non-aqueous chemistry, there are some IUPAC methods to measure pH, take a look at this reference: http://books.google.com/books?id=ieUi_y0...nts&f=false
I am not sure to understand at all, it is really difficult for me to extend or accept the pH definition to substances as lubricants (Mineral or PAOs based, and yes, some basestocks from the V group). I think that somehow i can't leave behind the basic definition stated by Sorenson.
Once i had a really bitter argument (5 years ago, as a matter of fact) with a boss when i refused to sign a pH lubricant QC report based on the color of a pH strip.
"pH measures the acidity of alkalinity of an aqueous solution. Since oil and water don't mix, pH values for oil are not accurate."
Has this argument been changed in a significative way?
In practical terms, the pH measure in lubricants is irrelevant or useless?
By the way, can't remember any ASTM test related exclusively to pH. Are there?
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