Salts are the chemicals consisting of a cation, that is a positively charged ion, metal and negatively charged anion – the acid rest. There is a lot of types of salts: normal, sour, the main, double, mixed, hydrate, complex. It depends on structures of a cation and anion. How it is possible to define the salt basis?
Instruction
1. Let's assume, you have four identical containers with hot solutions. You know that it is solutions of carbonic lithium, carbonic sodium, carbonic potassium and carbonic barium. Your task: to define what salt contains in each capacity.
2. Remember physical and chemical properties of compounds of these metals. Lithium, sodium, potassium – alkaline metals of the first group, their property are very similar, the activity amplifies from lithium to potassium. Barium – alkaline-earth metal of the second group. Its carbonic salt is well dissolved in hot water, but badly dissolved in cold. Stop! Here and the first opportunity at once to determine what capacity contains carbonic barium.
3. Cool tanks, for example, having placed them in a vessel with ice. Three solutions will remain transparent, and the fourth will quickly dim, the white deposit will begin to drop out. Here in it there is also a barium salt. Put this capacity aside.
4. It is possible to define quickly carbonic barium and in a different way. Serially cast a little solution in other container with solution of any sulfate salt (for example, sodium sulfate). Only barium ions, communicating about sulfate ions, instantly form a dense white deposit.
5. So, you defined carbonic barium. But how to you to distinguish salts of three alkaline metals? Quite just to make it, porcelain cups will be necessary for you for evaporation and a spirit-lamp.
6. Cast a small amount of each solution in a separate porcelain cup and evaporate water on spirit-lamp fire. Small kristallik are formed. Bring them in a flame of a spirit-lamp or the Bunsen burner – by means of steel tweezers, or a porcelain spoon. Your task is to notice color of the flashed flame "uvula". If it is lithium salt – color will be bright red. Sodium will paint a flame in saturated yellow color, and potassium – in purple-violet. By the way, if in the same way tested barium salt – color of a flame had to be green.