 What we can do with each of these though, of course, is we can start to get a bit of an idea of how these might look if we were to represent them in some sort of a model. So if we had a model and we knew that within our model we had some water molecules. The more water molecules we have the more dilute the solution is going to be. But we might also have some molecules of the acid. And what we might also find is that some of these water molecules also have some ionization that has left the anion from the acid floating around. So when we start to look at representing models of each of these we would be looking for the anions themselves and the degree to which they have been isolated. The formation of the hydronium ions the H plus which would become H3O plus like this when these are being added to water molecules. And also the fact that there may or may not still be molecules of the original acid remaining in the solution. So we need to make sure that we've got a I guess a visual representation of what strong and weak acids might look like as well as a mathematical value that helps to tell us something about them. The problem with the mathematical value is some of the some of the absolute values can be quite low and yet comparatively very high and therefore indicating quite strong solutions. In order to see that we're going to have to do some calculations and of course you're going to have a look at a few of these in class in order to help you understand some of these concepts in just a little bit more detail and also in terms of their application for particular types of problems. To take a couple of specific examples and go just a little bit further. Let's look at an example of a monoprotic and diprotic acids. One of which in each combination is strong. The other which is weak or weaker. So we've looked at hydrochloric acid. I'll leave the water out for the moment, but accept the fact that the H plus ion is usually in the form of hydronium ion. We know that this is pretty much a completion reaction. The equilibrium is so far to the right on this one that effectively we have no hydrogen chloride molecules in the water. We just have hydrogen ions and chloride ions. However, hydrofluoric acid on the other hand is not as strong as hydrochloric. We can see from the Ka value, this is the Ka value here, that the concentration of the hydrogen ions and fluoride ions has meant that we don't have complete ionization. So we would describe hydrochloric acid as a strong acid and hydrofluoric acid as a weak acid by comparison. And what I talked about before was the absolute values and 10 to the minus 4 looks like a small value, but compared to 10 to the minus 6 or 10 to the minus 10, it's quite large. So some of these terms are relative terms. So when I talk about strong and weak in relative terms, and it's useful to talk about these two, because both chlorine and fluorine are in the same group in the periodic table, so they're a nice thing to compare. What about something though like sulfuric acid? Now sulfuric acid is another acid that we know is a very strong acid, but when it ionizes, it ionizes to H plus and HSO4 minus. So this is what we call the first ionization, and the HSO4 itself is capable of acting as an acid and creating an H plus and an SO42 minus. And you might think this is the second ionization, and you might think that both of these would be the same, and therefore they would present a solution which is pretty much only hydrogen ions and sulfate ions. But in actual fact, we can see, and you can see that the order of magnitude is actually larger than the previous one. So this is stronger if we were to compare HSO4 minus with HF, we would say HSO4 minus is a stronger because it has a larger Ka value. Nevertheless, this doesn't fully ionize. So it's something to keep in mind with something like a di-protic acid like sulfuric acid, in that its second ionization is not always a completion. So in fact, when we're looking at sulfuric acid, we might actually say that the second one is more of an equilibrium. Now it still lies a long way to the right, it's still relatively strong compared to other acids, but it's not as strong as the original sulfuric acid that it started as. So these are just some of the different ways we can use the Ka values to make comparisons between the strengths of acids, and of course we can do likewise with the strength of base solutions. But we'll look at some more examples in future videos. Thanks for watching.