SOLUBILITY OF THE HYDROXIDES, SULPHATES AND CARBONATES OF THE GROUP 2 ELEMENTS IN WATER This page looks at the solubility in water of the hydroxides, sulphates and carbonates of the Group 2 elements - beryllium, magnesium, calcium, strontium and barium. Although it describes the trends, there isn't any attempt to explain them on this page - for reasons discussed later.You will find that there aren't any figures given for any of the solubilities. There are major discrepancies between the figures given by two common UK A level Data Books (Nuffield Advanced Science Book of Data, and Chemistry Data Book by Stark and Wallace). There are also important inconsistencies within the books (one set of figures doesn't agree with those which can be calculated from another set). I haven't been able to find data which I am sure is correct, and therefore prefer not to give any. The FactsSolubility of the hydroxides * The hydroxides become more soluble as you go down the Group.This is a trend which holds for the whole Group, and applies whichever set of data you choose.Some examples may help you to remember the trend:Magnesium hydroxide appears to be insoluble in water. However, if you shake it with water, filter it and test the pH of the solution, you find that it is slightly alkaline. This shows that there are more hydroxide ions in the solution than there were in the original water. Some magnesium hydroxide must have dissolved.Calcium hydroxide solution is used as "lime water". 1 litre of pure water will dissolve about 1 gram of calcium hydroxide at room temperature.Barium hydroxide is soluble enough to be able to produce a solution with a concentration of around 0.1 mol dm-3 at room temperature. Solubility of the sulphates * The sulphates become less soluble as you go down the Group.The simple trend is true provided you include hydrated beryllium sulphate in it, but not if the beryllium sulphate is anhydrous.The Nuffield Data