Let's just talk about stuff that you guys should remember, that strong acids are going to have a high dissociation constant. That means that they're very likely to dissociate fully. Okay? And that means, right, they fully dissociate in an aqueous solution. Remember that weak acids are going to have a smaller dissociation constant and what that means is that they're only going to partially dissociate in an aqueous solution. And that makes a huge difference because that means that they're going to have different pKa's. They're going to have different tendencies to donate protons. Now let's remember what is pKa. Well p, remember, stands for the negative log base 10. And then, remember that Ka stands just basically for products over reactants.
Now, I'm not going to make you guys calculate every single thing. But, check it out. I mean, products in this case are just dissociating into H+. And reactants are what happens before it fully dissociates. Does that make sense? So the Ka is basically the ratio of how much of my acid is going to actually become a proton. And that's what I care about. So therefore, if we're taking the negative log of this Ka, what that means is that the higher the Ka, basically the higher the chances of the molecule breaking apart and making ions, the lower the pKa is going to be.
So just like we had in pH, remember that your strongest acid was actually the one that was the lowest pH. It was, like, close to 0. Remember that basically pH is on a scale of 0 to 14 and remember that down here was the very acidic solution and then over at 14 was the very basic solution. So remember that if it was very acidic, it would have a very low pH, And in the same way, pKa is going to do the same thing. So your strongest acids are always going to have the lowest numbers for pKa. Does that make sense? And it's because we're using the negative log, not the positive. So it's always going to be the opposite. Cool so far? Awesome.
