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Reagent test Alcohols: Forms Lucas test in alcohols is a test to differentiate between primary, secondary, and tertiary alcohols. Alkaloids: Forms Froehde Liebermann Mandelin Marquis Mayer's Mecke Simon's: Amines, and amino acids: Forms Folin's: Barbiturates: Class Dille–Koppanyi Zwikker: Benzodiazepines: Class Zimmermann: Phytocannabinoids ...
Sodium iodide (chemical formula NaI) is an ionic compound formed from the chemical reaction of sodium metal and iodine. Under standard conditions, it is a white, water-soluble solid comprising a 1:1 mix of sodium cations (Na + ) and iodide anions (I − ) in a crystal lattice .
I 2 dissolves in the iodide-containing solution to give triiodide ions (I 3 −), which have a dark brown color. The triiodide ion solution is then titrated against standard thiosulfate solution to give iodide again using starch indicator: I − 3 + 2 e − ⇌ 3 I − (E 0 = +0.54 V) Together with reduction potential of thiosulfate: [1]
USP Tincture of Iodine is defined in the U.S. National Formulary (NF) as containing in each 100 mL, 1.8 to 2.2 grams of elemental iodine, and 2.1 to 2.6 grams of sodium iodide. Alcohol is 50 mL, and the balance is purified water. This "2% free iodine" solution has 0.08 mol/L of I 2, which provides about 1 mg of free iodine per 0.05 mL drop. The ...
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 ...
This clock reaction uses sodium, potassium or ammonium persulfate to oxidize iodide ions to iodine. Sodium thiosulfate is used to reduce iodine back to iodide before the iodine can complex with the starch to form the characteristic blue-black color. Iodine is generated: 2 I − + S 2 O 2− 8 → I 2 + 2 SO 2− 4. And is then removed:
A redox titration [1] is a type of titration based on a redox reaction between the analyte and titrant. It may involve the use of a redox indicator and/or a potentiometer. A common example of a redox titration is the treatment of a solution of iodine with a reducing agent to produce iodide using a starch indicator to help detect the endpoint.
The low solubility of silver iodide and lead iodide reflects the covalent character of these metal iodides. A test for the presence of iodide ions is the formation of yellow precipitates of these compounds upon treatment of a solution of silver nitrate or lead(II) nitrate. [2] Aqueous solutions of iodide salts dissolve iodine better than pure ...