 Let's try a couple of problems. So first of all we're going to write the solubility products for each of the salts below and then we're going to work out which of them would be the most soluble. So the first one is lead bromide, lead 2 bromide, so its formula will be PbBr2 and I'll just write out its dissolution equation. So there'll be one lead ion and there'll be two bromide ions so that's what it will look like and its solubility product expression will be concentration of the lead ion times the concentration of the bromide ion squared. Okay let's do the next one. Lead carbonate is PbCo3 that's going to dissolve into one lead ion and one carbonate ion and so its Ksp is simply going to be the concentration of the lead ions multiplied by the concentration of the carbonate ions and I'll leave you to try the other two for yourself. All right now let's look at the values of the Ksp and work out which one is the most soluble. Remember that if the Ksp is a large number it means that the concentrations of the ions must also be large because they get multiplied together to make the Ksp. So basically the larger the Ksp the more soluble the salt is. So out of these four to choose from it is the lead to chloride which has a Ksp of 1.7 times 10 to the minus 5 which has the highest Ksp and therefore it is the most soluble of all of them. This is all relative though. Obviously all of these numbers are quite small. In general lead salts are not very soluble but lead hydroxide for instance is 15 orders of magnitude less soluble than lead chloride. We would tend to refer to lead hydroxide as insoluble. Okay