一些物质的实验室制法（Laboratory method for the preparation of substances）.doc

一些物质的实验室制法（Laboratory method for the preparation of substances） Laboratory method for hydrogen chloride Hydrogen chloride is used in laboratories to react with salt and concentrated sulfuric acid without heating or slightly heating. Chemical equation is: NaCl+H2SO4 = =NaHSO4+HCl (concentrated) This reaction belongs to the type of gas produced by the reaction of solid powder with liquid. The gas making unit is the same as that produced in laboratory (see the laboratory process of chlorine gas). Hydrogen chloride is very soluble in water and has a greater density than air. It can only be collected by the upper air method. Hydrogen chloride has a strong pungent odor, the remaining exhaust after hydrogen chloride, can not escape in the room, water absorption. Laboratory method for hydrogen sulfide The lab is usually used with ferrous sulfide dilute hydrochloric acid or dilute sulfuric acid to produce hydrogen sulfide, which is chemical equation: = FeS+2HCl=FeCl2+H2S FeS+H2SO4 (=FeSO4+H2S = rare) Hydrogen sulfide is produced by means of the apparatus for the production of gases by the reaction of bulk solids with liquids (see the instrument for preparing gases in solid and liquid pharmaceuticals) in junior high volumes. Hydrogen sulfide is soluble in water and has a greater density than air. It should be collected by the upper air method. Test set whether the gas tank has been filled with hydrogen sulfide, the wet lead acetate test paper will be set at the gas bottle mouth, if the test paper immediately black, proved that the hydrogen sulfide in the bottle has been filled. Laboratory method of sulfur dioxide In laboratory, sodium sulfite reacts with concentrated sulfuric acid to produce sulfur dioxide. Chemical equation is: Na2SO3+H2SO4 = =Na2SO4+H2O+SO2 (concentrated) The gas making device is an instrument for producing gas by reacting solid powder with liquid (see instrument for making gas in solid and liquid medicine) in junior high volumes. Sulfur dioxide is soluble