Search results
Results from the WOW.Com Content Network
It is the acidic anhydride of chromic acid, and is sometimes marketed under the same name. [6] This compound is a dark-purple solid under anhydrous conditions and bright orange when wet. The substance dissolves in water accompanied by hydrolysis. [clarification needed] Millions of kilograms are produced annually, mainly for electroplating. [7]
Further condensation reactions can occur in strongly acidic solution with the formation of trichromates, Cr 3 O 2− 10, and tetrachromates, Cr 4 O 2− 13. [2] All polyoxyanions of chromium(VI) have structures made up of tetrahedral CrO 4 units sharing corners. [3] The hydrogen chromate ion, HCrO 4 −, is a weak acid: HCrO − 4 ⇌ CrO 2−
Chromic acid is an intermediate in chromium plating, and is also used in ceramic glazes, and colored glass. Because a solution of chromic acid in sulfuric acid (also known as a sulfochromic mixture or chromosulfuric acid) is a powerful oxidizing agent, it can be used to clean laboratory glassware, particularly of otherwise insoluble organic ...
Sarett's reagent: a solution of CrO 3 (pyridine) 2 in pyridine. It was popularized for selective oxidation of primary and secondary alcohols to carbonyl compounds. Collins reagent is a solution of the same CrO 3 (pyridine) 2 but in dichloromethane. The Ratcliffe variant of Collins reagent relates to details of the preparation of this solution ...
CrO3 dissolves in water to make a solution containing H+ and CrO4-- ions, which is a dilute solution of chromic acid. Interestingly, CrO3 shows acid properties without water being present e.g. CaO + CrO3 --> CaCrO4. It is an example of a "Lewis acid" which meets the (broader) definition of an acid suggested by the chemist G.N.Lewis in the 1920s.
Jones reagent is a solution prepared by dissolving chromium trioxide in aqueous sulfuric acid. To effect a Jones oxidation, this acidic mixture is then added to an acetone solution of the substrate. Alternatively, potassium dichromate can be used in place of chromium trioxide. The oxidation is very rapid and quite exothermic. Yields are ...
Collins reagent is especially useful for oxidations of acid sensitive compounds. Primary and secondary alcohols are oxidized respectively to aldehydes and ketones in yields of 87-98%. [5] Like other oxidations by Cr(VI), the stoichiometry of the oxidations is complex because the metal undergoes 3e reduction and the substrate is oxidized by 2 ...
Example Bjerrum plot: Change in carbonate system of seawater from ocean acidification.. A Bjerrum plot (named after Niels Bjerrum), sometimes also known as a Sillén diagram (after Lars Gunnar Sillén), or a Hägg diagram (after Gunnar Hägg) [1] is a graph of the concentrations of the different species of a polyprotic acid in a solution, as a function of pH, [2] when the solution is at ...