The iodine value (or "iodine adsorption value" or "iodine number") in chemistry is the mass of iodine in grams that is consumed by 100 grams of a chemical substance. An iodine solution is yellow/brown in color and any chemical group in the substance that reacts with iodine will make the color disappear at a precise concentration. The amount of iodine solution thus required to keep the solution yellow/brown is a measure of the amount of iodine sensitive reactive groups. This article or section includes a list of works cited or a list of external links, but its sources remain unclear because it lacks in-text citations. ... General Name, Symbol, Number iodine, I, 53 Chemical series halogens Group, Period, Block 17, 5, p Appearance violet-dark gray, lustrous Standard atomic weight 126. ... Water and steam are two different forms of the same chemical substance A chemical substance is any material with a definite chemical composition, no matter where it comes from. ...

One application of the iodine number is the determination of saturation of fatty acids as double bonds in fatty acids also react with iodine compounds. The higher the iodine number, the more unsaturated fatty acid bonds are present in a fat. [1] In a typical procedure the acid is treated with an excess of the Hanus solution which is a solution of iodobromine (BrI). Unreacted iodobromine is reacted with potassium iodide which converts it to iodine. The iodine concentration is then determined by titration with sodium thiosulfate. A unsaturated compound in chemistry is a chemical compound that contains carbon - carbon pi bonds such as a alkene or a alkyne. ... In chemistry, especially biochemistry, a fatty acid is a carboxylic acid often with a long unbranched aliphatic tail (chain), which is either saturated or unsaturated. ... In chemistry, especially biochemistry, a fatty acid is a carboxylic acid (or organic acid), often with a long aliphatic tail (long chains), either saturated or unsaturated. ... Potassium iodide is a white crystalline salt with chemical formula KI, used in photography and radiation treatment. ... Sodium thiosulfate (Na2S2O3) is a colorless crystalline compound that is more familiar as the pentahydrate, Na2S2O3•5H2O, an efflorescent, monoclinic crystalline substance also called sodium hyposulfite or “hypo. ...

Standard methods for analysis are for example ASTM D1959-97 and DIN 53241. ASTM International is an international voluntary standards organization that develops and produces technical standards for materials, products, systems and services. ... Look up din in Wiktionary, the free dictionary. ...

For a simple analysis, 0.2 grams of the fat is mixed with 20cm³ Wij's solution and 10cm³ 1,1,1-trichloroethane. It is then left in the dark for 30mins. Next, 15cm³ of 10% potassium iodide solution and 10cm³ of deionised water is added. This is then titrated against 0.1M sodium thiosulphate (VI) solution. 1cm³ of 0.1M sodium thiosulphate solution = 0.01269g of iodine. The difference between a control titration and the titration with the fat present multiplied by this factor gives the mass of iodine absorbed by the oil. The chemical compound 1,1,1-trichloroethane is a chlorinated hydrocarbon that was until recently widely used as an industrial solvent. ... Potassium iodide is a white crystalline salt with chemical formula KI, used in photography and radiation treatment. ... Sodium thiosulfate pentahydrate Sodium thiosulfate (Na2S2O3) is a colorless crystalline compound that is more familiar as the pentahydrate, Na2S2O3 · 5H2O, an efflorescent, monoclinic crystalline substance also called sodium hyposulfite or “hypo. ... General Name, Symbol, Number iodine, I, 53 Chemical series halogens Group, Period, Block 17, 5, p Appearance violet-dark gray, lustrous Standard atomic weight 126. ...

See also

• Saponification value
• Acid number