Qualitative chemical analysis / by C. Remigius Fresenius.

Date:
1869
Catalogue details

Licence: Public Domain Mark

Credit: Qualitative chemical analysis / by C. Remigius Fresenius. Source: Wellcome Collection.

Provider: This material has been provided by the Royal College of Physicians of Edinburgh. The original may be consulted at the Royal College of Physicians of Edinburgh.

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    Mix the acid with the water, and allow to cool_, then pour the mixture on the salt in lumps contained in a litre flask. Distil with a Liebig^s condenser. Put 50 c.c. of water in the receiver. When 300 c.c. have been obtained, stop the opera- tion. Put two or three drops of dilute sulphuric acid into the product. Kydrofluosilicic Acidi Take of Sand 100 grm. Fluor spar, in powder . . . ]00 grm. Strong sulphuric acid. . . . 350 c.c. Water 400 c.c. Wash the sand from dust, and dry thoroughly. Mix it with the fluor spar, also dry, and then with the sulphuric acid in a stone-ware bottle of one and a half or two litres capacity. Place the bottle in an iron pot filled with sand. Connect the neck of the bottle with a small empty bottle, and the latter again with a wide tube bent twice at right angles. Join the outer end of the tube to a funnel by means of Indian rubber, and immerse the mouth of the funnel just into the water. Towards the end of the process the heat requires to be pretty strong. Fluoride of silicon comes over, which decomposes with the water, forming hydrated silica and hydrofluosilicic acid. The hydrate of silica would at once stop up the mouth of the delivery tube if it dipped directly in the water. When the evolution of gas has ceased, throw the gelatinous paste upon a linen cloth, squeeze the fluid through, and afterwards filter it. Hydrofluosilicic acid must produce no precipitate in solu- tions of salts of strontium (sulphuric acid). Kydrosulphuric Acid. THE GAS. Hydrosulphuric acid is made by the action of dilute sul- phuric acid upon sulphide of iron. In large laboratories it may be stored in a gasometer, and supplied like coal gas. In small laboratories it is made when required, from sulphide of iron and dilute sulphuric acid. When the apparatus is done with, the evolution-bottle should be washed out, or the ferrous sulphate produced may
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