 Okay, so this one will be able to relate the value of the increasing acid strength to an actual number. Okay, so this would be a pKa type of problem. So order these in increasing acid strength. So you've got to know the pKa. So on a question like this, you've got to look at the pKa table, which I have to give you. So the pKa's of these acids are, well, for this first one, hydrogen sulfate and pKa is 1.99. For the second one, hypochromous acid, the pKa is 8.64. For acetic acid, it's 4.74 for phenol. And for nitrous acid, it's 3.15. So when you get these numbers and you're trying to put them in order, all you've got to do is take the lowest one and say that's the strongest acid, and take the highest one and say that's the weakest acid. So if we're going in increasing order, so that'd be lowest to highest or weakest to strongest, I guess I should say, weakest to strongest. So the weakest would be the one with the biggest number. So this would be 1. So what's less than 10? What's the next one with the last number? The hypochromous acid. It's going to be 2. Then we go to acetic acid, then nitrous acid, the strongest one is the hydrogen sulfate and anion at 5. So in order to put these in increasing order, you just got to look at the pKa values.