 Well, it's the Bronsted-Lauri definition that actually solves this problem, and it solves the problem for both examples. It relies on the fact that acids are proton donors. The simplest way to demonstrate the Bronsted-Lauri model for any of these is to simply say if we were to put a molecule of hydrogen chloride into water, what we would notice is the H plus ion is going to come from here. It's going to be donated from the molecular species, and it's going to go to the water molecule. What that's going to leave is a Cl minus as the H plus leaves it. It'll remain in solution, obviously, and an H3O plus ion. This is known as the hydronium ion, and it is the one that we are measuring when we look at things like pH, and we'll look at that in more detail later. The hydronium ion is an indicator that we have an acidic solution, and that the acid has donated a proton, an H plus ion, to the water molecule to form this particular species. We can actually have a look at pairs, and we'll have a look at the Bronsted-Lauri model in a little bit more detail later on. But we can actually pair each of these up. We can look at an acid that has lost or donated its proton, and has become what we call a conjugate base, and the substance which acts as a base, and in this case the water actually acts as a base, and accepts that proton, and therefore the hydronium ion would be referred to as the conjugate acid. And so we have some some pairs here. An acid and its conjugate base are one pair, and a base and its conjugate acid are another pair, and they're related to each other by the hydrogen ion or the proton. So the proton is either lost from one species to its conjugate or gained from one species to its conjugate. We can do exactly the same thing assuming that bases are proton acceptors. So if we looked at the let's go back a bit to the carbonate example. So CO3 2 minus, this is the carbonate ion that we get from something like zinc carbonate, from sodium carbonate, and so on. If we again look at water, water's nice universal substance, and it's good for looking at these sorts of examples, then if this is a base, then that means according to the Bronsted-Lauri model, it's a proton acceptor. So this time the H plus has actually kind of come from the water to our to our base. That means that the CO3 becomes an HCO3 minus, its charge has changed, and the water molecule having lost a proton now becomes hydroxide. So you can see that's where we have that link back to the Arrhenius definition. So carbonates do actually liberate more hydroxide ions in solution. It's just they don't do it, obviously. You have to kind of work through it. Notice now that the water which was acting as a base in our previous reaction is now acting as an acid, and our bicarbonate or hydrogen carbonate ion is our conjugate acid, and the hydroxide ion is the conjugate base. And we'll look at these in a lot more detail as we explore the Bronsted-Lauri model because it is such a good example of a good way of looking at wider range of acids and bases and being able to classify lots of different types of reactions. Once again, we can identify our acid and our conjugate base and our base with our conjugate acid, but we'll look at these pairs in a little more detail as we go further along. Thanks for watching.