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The reagent is an alkaline solution of potassium permanganate. Reaction with double or triple bonds (R 2 C=CR 2 or R−C≡C−R) causes the color to fade from purplish-pink to brown. Aldehydes and formic acid (and formates) also give a positive test. [43] The test is antiquated. Baeyer's reagent reaction
It involves two steps, namely the titration of the analyte with potassium permanganate solution and then the standardization of potassium permanganate solution with standard sodium oxalate solution. The titration involves volumetric manipulations to prepare the analyte solutions.
First step is to plot the absorbance(A) values of standard solution against molar concentrations (c) of the known solution. Then the best straight line is plotted, passing through the origin. The experimental points are plotted as per Beer’s law: A= E*c*l where E= molar extinction coefficient and l= optical path length usually 1 cm.
This reaction illustrates the relatively rare role of hydroxide as a reducing agent. The concentration of K 2 MnO 4 in such solutions can be checked by measuring their absorbance at 610 nm. The one-electron reduction of permanganate to manganate can also be effected using iodide as the reducing agent: 2 KMnO 4 + 2 KI → 2 K 2 MnO 4 + I 2
The white smoke-like vapor produced by the reaction is a mixture of carbon dioxide gas and water vapor. Since the reaction is highly exothermic, initial sparking occurs, followed by a lilac- or pink-colored flame. [9] When energy or heat is added to electrons, their energy level increases to an excited state.
The turnover-limiting step of the reaction is the hydrolysis step; therefore, sulfuric acid is added to increase the rate of this step. [ 17 ] [ 18 ] Manganese is also used in dihydroxylation and is often chosen when osmium tetroxide methods yield poor results. [ 18 ]
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 basic chemical reaction involved in the Hummers' method is the oxidation of graphite, introducing molecules of oxygen to the pure carbon graphene. The reaction occurs between the graphene and the concentrated sulfuric acid with the potassium permanganate and sodium nitrate acting as catalysts.