Hydrochloric (chlorohydrogen) acid has a chemical formula of NSl. This substance represents itself transparent caustic liquid, colourless or with a weak yellowish shade. Its density is about 1.2 grams / cubic centimeter. Hydrochloric acid and also its derivatives are widely used in different industries. By what simple and evident chemical reactions it is possible to define this acid?
Instruction
1. Let's assume, you have several numbered test tubes with colourless liquids. You know that at least one of them – hydrochloric acid. Cast from test tubes gradually liquids in other test tubes numbered in the same way then add to everyone on a piece of active metal (that is standing in an electrochemical number of tension is more left than hydrogen), but not alkaline or alkaline-earth. Very well zinc will be suitable for this experience. In that test tube where impassioned reaction with allocation of a large amount of gas will at once begin, there is acid as metal forces out hydrogen, taking its place and forming salt. Reaction takes place according to the following scheme: Zn+2 HCl=ZnCl2+H2.
2. Why alkaline or alkaline-earth metal will not approach? The fact is that they give similar reaction with release of hydrogen not only at contact with acid, but also at connection with water. Therefore additional experiments would be necessary that would complicate a task.
3. To prove that the emitted gas – hydrogen, it is necessary to bring together him in the turned test tube by means of a curved glass tube and capacity with a hydrolock, and then to bring the smoldering splinter by the open end of a test tube. Loud cotton has to be distributed. For precaution it is necessary to wind before it a test tube some matter or a strip of thin rubber not to allow injuries if glass bursts.
4. You proved that the test tube where zinc was placed, contained acid. But to learn what is acid, it is necessary to make one more experiment. For the substances containing chloride ion there is very evident high-quality reaction based that chloride silver (AgCl) – one of the most slightly soluble substances.
5. Flow a little solution of nitrate silver (lyapis) in the first test tube. If the white deposit instantly drops out, in capacity there was hydrochloric acid. Reaction proceeds according to the following scheme: HCl+AgNO3=AgCl+HNO3.