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Hydrofluoric acid is a solution of hydrogen fluoride (HF) in water.Solutions of HF are colorless, acidic and highly corrosive.A common concentration is 49% (48-52%) but there are also stronger solutions (e.g. 70%) and pure HF has a boiling point near room temperature.
Hydrogen fluoride is typically produced by the reaction between sulfuric acid and pure grades of the mineral fluorite: [14] CaF 2 + H 2 SO 4 → 2 HF + CaSO 4 About 20% of manufactured HF is a byproduct of fertilizer production, which generates hexafluorosilicic acid .
Unlike other hydrohalic acids, such as hydrochloric acid, hydrogen fluoride is only a weak acid in water solution, with acid dissociation constant (pK a) equal to 3.19. [36] HF's weakness as an aqueous acid is paradoxical considering how polar the HF bond is, much more so than the bond in HCl, HBr, or HI. The explanation for the behavior is ...
This neutralization reaction forms hydrogen fluoride (HF), the conjugate acid of fluoride. In aqueous solution, fluoride has a pK b value of 10.8. It is therefore a weak base, and tends to remain as the fluoride ion rather than generating a substantial amount of hydrogen fluoride. That is, the following equilibrium favours the left-hand side in ...
In water, ammonium bifluoride exists in chemical equilibrium with hydrofluoric acid and heating releases hydrogen fluoride gas. [9] Consequently, there is an equivalent toxicological risk as is present with hydrofluoric acid, and the same safety precautions apply. [10] [9] Ammonium bifluoride is used in some automotive wheel cleaning products.
Sodium bifluoride reacts with water or moist skin to produce hydrofluoric acid. It also gives off hydrofluoric acid and hydrogen gas when it is heated to a gaseous state. The chemical can decompose upon contact with strong acids, strong bases, metal, water, or glass. [3] Sodium bifluoride also engages in violent reactions with chromyl chloride ...
The Torrance Refinery has been safely and reliably manufacturing alkylate for transportation fuels using hydrogen fluoride (HF), including modified hydrogen fluoride (MHF), in its Alkylation Unit ...
Hexafluorosilic acid is only stable in hydrogen fluoride or acidic aqueous solutions. In any other circumstance, it acts as a source of hydrofluoric acid. Thus, for example, hexafluorosilicic acid pure or in oleum solution evolves silicon tetrafluoride until the residual hydrogen fluoride re-establishes equilibrium: [7] H 2 SiF 6 ⇌ 2 HF(l ...