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The optional second step (for bare silicon wafers) is a short immersion in a 1:100 or 1:50 solution of aqueous HF (hydrofluoric acid) at 25 °C for about fifteen seconds, in order to remove the thin oxide layer and some fraction of ionic contaminants. If this step is performed without ultra high purity materials and ultra clean containers, it ...
The Grignard reaction between phenylmagnesium bromide (1) and carbon dioxide in the form of dry ice gives the conjugate base of benzoic acid (2). The desired product, benzoic acid (3), is obtained by the following work-up: [2] Synthesis of benzoic acid with work-up step in red.
Hydrochloric acid is a strong inorganic acid that is used in many industrial processes such as refining metal. The application often determines the required product quality. [25] Hydrogen chloride, not hydrochloric acid, is used more widely in industrial organic chemistry, e.g. for vinyl chloride and dichloroethane. [8]
Acid–base extraction is a subclass of liquid–liquid extractions and involves the separation of chemical species from other acidic or basic compounds. [1] It is typically performed during the work-up step following a chemical synthesis to purify crude compounds [2] and results in the product being largely free of acidic or basic impurities.
Acidic drain cleaners usually contain sulfuric acid at high concentrations. [1] It can dissolve cellulose, proteins like hair, and fats via acid hydrolysis . While there are many methods for unclogging drains, one of the most effective solutions is using hydrochloric acid (HCl), a powerful chemical cleaner.
The 1st analytical group of cations consists of ions which form insoluble chlorides. As such, the group reagent to separate them is hydrochloric acid, usually used at a concentration of 1–2 M. Concentrated HCl must not be used, because it forms a soluble complex ([PbCl 4] 2−) with Pb 2+. Consequently, the Pb 2+ ion would go undetected.
However, since blood is buffered with carbonate at physiological pH (near 7.4), free-base amines will be rapidly converted back into their acid form. In fact, 94.19% of cocaine will exist as the acid form under equilibrium at pH=7.4, calculated using the Henderson–Hasselbalch equation assuming a pKa of 8.61. [1]
The main steps in this process are the production of chlorobenzene from benzene, hydrochloric acid and oxygen, and the subsequent hydrolysis of chlorobenzene to phenol. [4] The first step uses either a copper or iron chloride catalyst and exposes the materials to air at 200–250 °C.