Search results
Results From The WOW.Com Content Network
The purplish-black color of solid potassium permanganate, and the intensely pink to purple color of its solutions, is caused by its permanganate anion, which gets its color from a strong charge-transfer absorption band caused by excitation of electrons from oxo ligand orbitals to empty orbitals of the manganese(VII) center.
A permanganate (/ p ər ˈ m æ ŋ ɡ ə n eɪ t, p ɜːr-/) [1] is a chemical compound with the manganate(VII) ion, MnO − 4, the conjugate base of permanganic acid. Because the manganese atom has a +7 oxidation state, the permanganate(VII) ion is a strong oxidising agent. The ion is a transition metal ion with a tetrahedral structure. [2]
Potassium permanganate will decompose into potassium manganate, manganese dioxide and oxygen gas: 2 KMnO 4 → K 2 MnO 4 + MnO 2 + O 2. This reaction is a laboratory method to prepare oxygen, but produces samples of potassium manganate contaminated with MnO 2. The former is soluble and the latter is not.
The chemical chameleon reaction shows the process in reverse, by reducing violet potassium permanganate first to green potassium manganate and eventually to brown manganese dioxide: [1] [2] [5] KMnO 4 (violet) → K 2 MnO 4 (green) → MnO 2 (brown/yellow suspension) Blue potassium hypomanganate may also form as an intermediate. [6]
4, also known as manganate(VI) because it contains manganese in the +6 oxidation state. [1] Manganates are the only known manganese(VI) compounds. [2] Other manganates include hypomanganate or manganate(V), MnO 3− 4, permanganate or manganate(VII), MnO − 4, and the dimanganate or dimanganate(III) Mn 2 O 6− 6. A manganate(IV) anion MnO 4−
A positive reaction of Schaeffer's test, which uses the reaction of aniline and nitric acid on the surface of the mushroom, is indicated by an orange to red color; it is characteristic of species in the section Flavescentes. The compounds responsible for the reaction were named schaefferal A and B to honor Schäffer. [3]
Scientists at University College London created what they are calling the "world's thinnest spaghetti." Don't expect to see this item on restaurant menus any time soon, however.
Dragendorff's reagent is prepared by mixing a concentrated solution of potassium iodide with a solution of bismuth subnitrate in a diluted acid (acetic acid or tartaric acid, hydrochloric acid or sulfuric acid is rarely being used) as a low pH is mandatory for this reagent. [2] The formation is as follows: