I understand that to measure a pH you have to have an aqueous solution, but to say that solids don't have a pH is false.
Well, I can clearly see the point here but substances are referred to acidic or alkaline, and yes they are tagged with a pH. But we can say that they will not have a pH in the absence of water. I`m guessing a substance`s pH is defined for 1 mole of that substance measured in a certain amount (say 1000ml or 1dm^3) of water. So a solid has pH/mol and a solution has pH mol dm^-3. 2 different things however one notates the water, one doesnt. But the water must always be noted as pH can only be derived from an aqueous solution. So even though a substance has a scalar value of pH, even though not noted, there must be an amount of water which that amount of substance achives the value of pH it is labelled as pH can only be measured in an aqueous solution. So dont think of it as pH, think of the scale of pH as having: A value for H3O+ ion dissociation in aqueous water A value of mass of our acidic/alkaline substance A value of the amount of aqueous solution (e.g water) in the solution. Or just think of it as H3O ions and concentration because concentration is the ratio of mass to aqueous solution, therefore taking the 2 variables into account with it.
I`m not trying to be a smart arse of any form, I just love scientific debate as it complements knowledge
Okay that was all the info I could personally give and decided to consult google. From a Q/A website:Cant take the pH of a solid. pH is the -Log of the Molarity of free protons in solution. Molarity is how much stuff per liter of liquid. By definition you cannot have the pH of a solid because it must be in solution. You can find out a solids pKa, which is how strong an acid or base a solid is, by disloving it in a set amount of liquid and checking its pH. And the definition for pKa is: pKa : The larger the value of pKa, the smaller the extent of dissociation. A weak acid has a pKa value in the approximate range −2 to 12 in water. Acids with a pKa value of less than about −2 are said to be strong acids; a strong acid is almost completely dissociated in aqueous solution, to the extent that the concentration of the undissociated acid becomes undetectable. So Rastakolnikov, the scale of pH applied to solids is clearly something else, its called pKa and is calculated using different mathematics.
As proof for the difference of pH&pKa, it can be seen that the scale is different. The pKa will range from -2 to 12 where pH will range from 0 to 14. As maths defines scientific concepts, this one is clearly defined differently.
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