Fluoric acid or ftoristovodorodny acid – the colourless liquid representing solution of gaseous fluoric hydrogen in water.
Small impurity of fluoric acid strongly lowers a water freezing point.
When heating of the diluted acid at first water and very weak solution of fluoric acid is driven away, at 120 ° C the azeotropny mix containing 35,37% of fluoric acid begins to be overtaken.
Fluoric acid – strong acid.
Fluoric acid destroys glass, interacting with dioxide of silicon which is in composition of glass, with formation of a gaseous kremnetetraftorid. Fluoric acid dissolves some metals with formation of fluorides. Fluorides of calcium, barium, strontium are almost insoluble in water. Fluorides of copper, nickel, cadmium and chrome (III), all other fluorides are almost insoluble, including fluoride of silver are readily soluble.
Fluoric acid dissolves zinc and iron, very slowly lead, copper and silver, does not react with gold and platinum.
The main way of receiving fluoric acid calcium fluorite reaction with sulfuric acid which is carried out in the tubular rotating and shnekovy furnaces at 120-180os. Reactionary gases clear of dust, condense from them fluoric acid and subject it to two-level rectification.
In laboratory it is convenient to receive ftoristovodorodny acid thermal decomposition of hydrofluorides.
- for destruction of silicate rocks
- dissolution of metals (tantalum, zirconium, niobium, etc.)
- hydrogenation catalyst
- dehydrogenation catalyst
- the alkylation catalyst in organic chemistry
- reagent in production of hladon and ftoroplast
- initial substance for receiving fluorine
- production of ftorsulfonovy acid
Store fluoric acid in paraffin, chlorvinyl, platinum, ftoroplastovy and polyethylene vessels, and also in organic glass vessels.
The ftoroplastovy ware is very good for work with acid. Fluoric acid can be poured in the glasses which are previously covered with a paraffin layer. The ware from wax, paraffin, ceresin and gutta-percha is not really reliable.
In large volumes ftorovodorodny acid is stored in steel tight tanks and tanks, and also in the cylinders of ammoniac type having protective coloring with a red strip.
Fluoric acid is poisonous, irritates airways, is the strongest water taking away substance, getting on skin, causes severe burns and ulcers, and at a long exposition – a carbonization.
Hit of fluoric acid under nails is especially dangerous.
It is necessary to work with fluoric acid under good draft, using platinum ware, it is desirable in rubber gloves.
Fluoric acid can cause the corroding action on skin not at once, and in several hours.
The smoke which is formed in the presence of ammonia is also poisonous.
At poisoning with vapors of fluoric acid to do soda inhalations, to drink warm milk with Borjomi, to apply mustard plasters, banks.
At burns fluoric acid immediately skin is washed out flowing water within several hours until the turned white surface of skin does not redden. Then impose freshly cooked 20% - ny suspension of oxide of magnesium in glycerin.
Fluoric acid is flammable. It is possible to apply water to suppression.
In the presence in air of fluoric hydrogen it is necessary to put on the isolating gas mask (an oxygen mask).