Fourth group of cations barium, strontium, and calcium

30 FOURTH GROUP OF CATIONS BARIUM, STRONTIUM, AND CALCIUM 

The reagent is colourless, and displays an alkaline reaction because of hydrolysis  

The reagent is decomposed by acids (even by acetic acid), when carbon dioxide gas is formed  

The reagent has to be used in neutral or slightly alkaline media. 

The three alkaline earth metals decompose water at different rates, forming hydroxides and hydrogen gas. Their hydroxides are strong bases, although with different solubilities barium hydroxide is the most soluble, while calcium hydroxide is the least soluble among them. Alkaline earth chlorides and nitrates are very soluble the carbonates, sulphates, phosphates, and oxalates are insoluble. The sulphides can be prepared only in the dry they all hydrolyse in water, forming hydrogen sulphides and hydroxides, e.g. 

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