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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.
When dilute, hydrofluoric acid behaves like a weak acid, unlike the other hydrohalic acids, due to the formation of hydrogen-bonded ion pairs [H 3 O + ·F −]. However concentrated solutions are strong acids, because bifluoride anions are predominant, instead of ion pairs. In liquid anhydrous HF, self-ionization occurs: [10] [11] 3 HF ⇌ H 2 ...
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 ...
Fluoroantimonic acid is the strongest superacid based on the measured value of its Hammett acidity function (H 0), which has been determined for various ratios of HF:SbF 5. The H 0 of HF is −15. [5] A solution of HF containing 1 mol % of SbF 5 is −20. The H 0 is −21 for 10 mol%. For > 50 mol % SbF 5, the H 0 is between −21 and −23.
Buffered oxide etch (BOE), also known as buffered HF or BHF, is a wet etchant used in microfabrication. It is a mixture of a buffering agent, such as ammonium fluoride NH 4 F, and hydrofluoric acid (HF). Its primary use is in etching thin films of silicon nitride (Si 3 N 4) or silicon dioxide (SiO 2), by the reaction:
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 ...
The dust is still settling following the Tesla and SpaceX pioneer’s role last week in sabotaging a year-end House spending package, which was eventually replaced by a smaller stopgap law to keep ...
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 ...