Search results
Results from the WOW.Com Content Network
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.
In acid catalysis and base catalysis, a chemical reaction is catalyzed by an acid or a base. By Brønsted–Lowry acid–base theory, the acid is the proton (hydrogen ion, H +) donor and the base is the proton acceptor. Typical reactions catalyzed by proton transfer are esterifications and aldol reactions.
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: SiO 2 + 4HF + 2NH 4 F → (NH 4) 2 SiF 6 + 2H 2 O
Out of the four stable halogens, only fluorine and chlorine have reduction potentials higher than that of oxygen, allowing them to form hydrofluoric acid and hydrochloric acid directly through reaction with water. [17] The reaction of fluorine with water is especially hazardous, as an addition of fluorine gas to cold water will produce ...
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 .
In water, measurable pK a values range from about −2 for a strong acid to about 12 for a very weak acid (or strong base). A buffer solution of a desired pH can be prepared as a mixture of a weak acid and its conjugate base. In practice, the mixture can be created by dissolving the acid in water, and adding the requisite amount of strong acid ...
This neutralization reaction forms hydrogen fluoride (HF), the conjugate acid of fluoride. In aqueous solution, fluoride has a p K 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.
In the end, this accumulation of positive charge leads to the dissolution of the substrate by hydrofluoric acid. [1] MACE consists of multiple individual reactions. At the metal particle, the oxidizing agent is reduced. In the case of hydrogen peroxide this can be written down as follows: