The solution is boiled until no more bubbles of oxygen are produced. The solution is heated further to concentrate it, and then concentrated ethanoic acid is added to acidify it. Orange crystals of potassium dichromate are formed on cooling. The reduction of dichromate(VI) ions with zinc and an acid Dichromate(VI) ions (for example, in potassium dichromate(VI) solution) can be reduced to chromium(III) ions and then to chromium(II) ions using zinc and either dilute sulfuric acid or hydrochloric acid. Hydrogen is produced from a side reaction between the zinc and acid. This must be allowed to escape, but you need to keep air out of the reaction. Oxygen in the air rapidly re-oxidises chromium(II) to chromium(III). An easy way of doing this is to put a bit of cotton wool in the top of the flask (or test-tube) that you are using. This allows the hydrogen to escape, but stops most of the air getting in against the flow of the hydrogen. The reason for the inverted commas around the chromium(III) ion is that this is a simplification. The exact nature of the complex ion will depend on which acid you use in the reduction process. This has already been discussed towards the top of the page.

Chrome alum Chrome alum, also known as chromium potassium sulfate, is a chemical compound. Its chemical formula is KCr(SO4)2. It contains chromium, potassium, and sulfate ions. The chromium is in its +3 oxidation state. Properties It is a dark purple solid. It is normally attached to extra water molecules. It dissolves in water. Preparation It is made by reducing potassium dichromate with sulfur dioxide. Uses It was used in making leather; now chromium(III) sulfate is used instead.

ethanol reacts with the potassium dichromate, reducing the dichromate ion to the chromium (III) ion. This reduction results in a change of the solution's color A breathalyzer or breathalyser (a portmanteau of breath and analyzer/analyser), also called an alcohol meter, is a device for measuring breath alcohol content (BrAC). It is commonly utilized by law enforcement officers whenever they initiate traffic stops. The name is a genericized trademark of the Breathalyzer brand name of instruments developed by inventor Robert Frank Borkenstein in the 1950s. Acetone (from keto diets or diabetes) Methanol or isopropanol exposure Some mouth sprays or breath fresheners. Photovoltaic assay The photovoltaic assay, used only in the dated photoelectric intoximeter, is a form of breath…

Mutagenic activity of copper(II) chromate and dichromate complexes with polypyridines. Copper(II) chromate and dichromate complexes with 2,2'-bipyridyl and 1,10-phenathroline were tested for their mutagenic activity in the standard Ames test. All of six tested complexes exhibited markedly lower mutagenic activity than the reference compounds--potassium dichromate and sodium chromate. The blockage of Cr(VI) reduction capability in the presence of the complex Cu2+ ion and the competition between copper and chromium ions in the interaction with cellular components are discussed in the light of the results of our previous chemical study. Published in Biometals : an international journal on the role of metal ions in biology, biochemistry, and medicine (1992)

Abstract The effects of trivalent (chromium chloride) and hexavalent (potassium dichromate) chromium have been studied on the nucleic acids of cultured mammalian cells (BHK hamster fibroblast line), commercial DNA and RNA, and synthetic polynucleotides of known base composition. Modifications of UV absorption spectra and alterations of thermal denaturation and renaturation patterns have been observed by directly treating purified nucleic acids, as well as by examining nucleic acids extracted from cells treated with chromium compounds. Cr(III) interacts with nucleic acid bases, mostly guanine and cytosine, but also with phosphate groups, leading to deprotonation of bases as well as intramolecular cross-links, sandwich complexes between bases and chelation between bases and phosphates. Such interactions destabilize the DNA structure. On the contrary, stabilization of RNA, due to intramolecular metal bonds between nitrogen bases in GC-rich regions, is mainly produced. The kind of interaction of Cr(III) with nucleic acids is not significantly different when intact BHK cells are treated. Cr(VI) interacts similarly with DNA and RNA giving instead different effects when purified nucleic acids or intact cells are treated. Treatment of purified DNA produces breakages in the polynucleotide chain due to the oxidizing power of Cr(VI). In intact cell treatments, changes in the properties of DNA are observed. These could result from the combined action of Cr(III), produced by the intracell

Hexavalent chromium ion [Cr(VI)] poses serious environmental risks due to its high toxicity and ability to cross biological membranes, leading to organ damage and genetic mutations. This study presents a new practical method for removing Cr(VI) ions from wastewater using nitrogen-doped activated carbon (AC600) prepared by pyrolyzing sawdust with ZnCl₂ at 600 °C. Thereafter, batch experiments were conducted using different adsorbent doses (0.5-2.5 g L^-1) and Cr(VI) ion concentrations (100-400 mg/L) at pH ranging from 1 to 12. Results revealed that Cr(VI) ions sorption on AC600 followed both linear and adsorption isotherm models at low sorbent doses (< 1.5 g/L). At higher doses, sorption shifted toward a hyperbolic adsorption pattern. Overall sorption data fitted well with both the Freundlich and Temkin isotherm models. Cr(VI) ions removal efficiency increased with contact time, following a sharp rise within the first 20-40 min of contact, while equilibrating within approximately 60-80 min. However, this efficiency decreased as pH increased. The highest efficiency (95-99%) was achieved using 2.5 g of AC600 to treat 1 L of water containing 100-150 mg/L of Cr(VI) ions within 2 h. For higher Cr(VI) ion concentration (200-250 mg/L), the efficiency decreased to 88-90%. The kinetics of Cr(VI) ion sorption on activated carbon followed the Pseudo-Second-Order model at low to moderate AC600 doses and low Cr(VI) ion concentrations. At higher doses and Cr(VI) levels, the power function and intraparticle diffusion models provided better fits. A maximum adsorption % could be achieved by using 2.5 g of AC600 and a Cr(VI) ion solution at 100 mg/L, according to results from an optimization of adsorption parameters using response surface methodology (RSM).