ph

[annikaying]

Can ph be above 14 or below 0? Or is there a specific cap at those values?

[Connor Chappell 2B]

THe scale is not restricted between 0 and 14 for pH or pOH. However, at room temperature, this scale is restricted. This is because the value of kw (autoprolysis of water) is 10^-14 and thus, the maximum valuue is set to be 14, with the lowest value being 0. In many of the cases, we are assuming that the reaction is at room temperature.

[Ruby Tang 2J]

Yes! pH can definitely be above 14 or below 0. An example is 12 M HCl, which has a pH of about -1.08. If we consider mathematically that pH=-log[H+], then we know that if [H+] is greater than 1, pH has to be below 0.

[Hailey Kim 4G]

Yes, the pH can be less than 0 and greater than 14; however, is it more likely for the pH to fall in the 0-14 range.

[Megan Kirschner]

The way I like to think of it is it can lie outside of the 0 to 14 range, but pH + pOH must equal 14 when added together.

[smurphy1D]

when trying to find the pH or poH of something, do We take the - log of the opposite concentration of the one we are trying to find?

[MinuChoi]

when trying to find the pH or poH of something, do We take the - log of the opposite concentration of the one we are trying to find?

No; pH = -log[H+] and pOH=-log[OH-].
But you can use pH to find pOH and vice versa because pH + pOH = 14.

[Manav Govil 1B]

The pH scale is not restricted per se, but it is at room temp. I don't think that they will ever ask you a question where the answer is pH 15.45 though. Oh, and pH can never be negative.

[kausalya_1k]

i believe that it's possible, but for the scope of this class i don't think we don't need to worry about that

[Areena H 2K]

I believe the ph can be above or below 14 but generally, the range it falls under is 0-14

[preyasikumar_2L]

At different temperatures, the pH scale can go beyond the standard 0 to 14, because at different temperatures the autoprotolysis value of water is different from 10^-14, but we do not need to worry about this in this class (for now).