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A bottle of iodine solution used on apples to determine the correct harvest time. The chart shows the level of residual starch. The cut surface of an apple stained with iodine, indicating a starch level of 4–5. The iodine–starch test is a chemical reaction that is used to test for the presence of starch or for iodine. The combination of ...
The iodine clock reaction is a classical chemical clock demonstration experiment to display chemical kinetics in action; it was discovered by Hans Heinrich Landolt in 1886. [1] The iodine clock reaction exists in several variations, which each involve iodine species (iodide ion, free iodine, or iodate ion) and redox reagents in the presence of ...
It is advised to check the references for photos of reaction results. [1] Reagent testers might show the colour of the desired substance while not showing a different colour for a more dangerous additive. [2] For this reason it is essential to use multiple different tests to show all adulterants.
The iodine content and thus the active chlorine content can be determined with iodometry. [3] The determination of arsenic(V) compounds is the reverse of the standardization of iodine solution with sodium arsenite, where a known and excess amount of iodide is added to the sample: As 2 O 5 + 4 H + + 4 I − ⇌ As 2 O 3 + 2 I 2 + 2 H 2 O
Schultze reagent (also known as Chlor-Zinc-Iodine Solution) [1] is an oxidizing mixture consisting of a saturated aqueous solution of potassium chlorate KClO 3 and varying amounts of concentrated nitric acid HNO 3. It is commonly used in palynologic macerations. It was invented by Max Schultze.
Melzer's reagent is an aqueous solution of chloral hydrate, potassium iodide, and iodine.Depending on the formulation, it consists of approximately 2.50-3.75% potassium iodide and 0.75–1.25% iodine, with the remainder of the solution being 50% water and 50% chloral hydrate.
The CK test is a less commonly used variation that reverses the order of the application of chemicals. It is used in special cases when testing for orange colour produced by barbatic acid or diffractaic acid, such as is present in Cladonia floerkeana. [8] Lugol's iodine is another reagent that may be useful in identifying certain species. [16]
Despite its name, the reagent does not in fact contain biuret [(H 2 N−CO−) 2 NH]. The test is named so because it also gives a positive reaction to the peptide-like bonds in the biuret molecule. In this assay, the copper(II) binds with nitrogen atoms present in the peptides of proteins. In a secondary reaction, the copper(II) is reduced to ...