Oranges potassium

Ionic compounds containing polyatomic ions. Ftitassium dichromate (KjCtjOj, orange), potassium permanganate (KMnOa, very dark purple), and potassium nitrate (KNO3. white). 

Pipette 25 mL of the bismuth solution (approx. 0.01 M) into a 500 mL conical flask and dilute with de-ionised water to about 150 mL. If necessary, adjust the pH to about 1 by the cautious addition of dilute aqueous ammonia or of dilute nitric acid use a pH meter. Add 30 mg of the xylenol orange/potassium nitrate mixture (see Section 10.50) and then titrate with standard 0.01 M EDTA solution until the red colour starts to fade. From this point add the titrant slowly until the end point is reached and the indicator changes to yellow. 

Figure 15.5 Orange potassium dichromate(vi) slowly turns green as it oxidises ethanol to ethanoic acid. Potassium manganate(vn) turns from purple to colourless.

Golden Yellow —Potassium chlorate, 8 oz. barium nitrate, 2 ox shellac, 2 ox sodium oxalate, 1)4 ozj stearine, )4 oz, a Orange.—Potassium chlorate 8 ox strontium chlorate, 1 oz. barium nitrate, 2 ox shellac, 2 oz. sodium oxalate, 1)4 oz... 

Orange potassium chlorochromate can be prepared simply by dissolving K2Cr207 in hot 6 M HC1 and crystallizing, or by chlorination of Cr202 with oxalylchloride. It can be recrystallized from HC1 but is hydrolyzed by water ... 

Colour Tests. Coniferyl Alcohol—orange Diazotisation—red Liebermann s Test—red-orange Potassium Dichromate—blue-green (2 min). 

Colour Tests. Ammoniacal Silver Nitrate—red/brown Ferric Chloride—green Liebermann s Test—black Marquis Test— brown— black Methanolic Potassium Hydroxide—orange-pink Nessler s Reagent—black Palladium Chloride—orange Potassium Dichromate—green— brown Sulphuric Acid—yellow. 

GUNPOWDER, or black powder, is a mixture of saltpetre, sulphur and carbon. Early Chinese recipes used equal weights to make a fast burning, but not explosive, powder. A composition that matches well the chemistry ctf the reaction is 15 parts saltpetre, 2 parts sulphur and 3 parts charcoal. Mix the ingedients while damp, using pressure to make a dense cake which can be broken into grains when dry. For most explosive results use refined saltpetre. Metal salts can add colour to the explosion, e.g. sodium salts for yellow or orange, potassium salts for purple, and strontium salts for red. This is the basis of fireworks. 

A fascinating feature of chromium chemistry is the many coiorfui compounds it produces, such as bright yellow potassium chromate and brilliant orange potassium dichromate. These and other colored compounds are responsible for the element s name. Chromium comes from the Greek word khroma, which means "color." Trace amounts of chromium in otherwise-colorless mineral crystals produce the brilliant colors of rubies and emeralds. 

The brilliant colors of these chromium compounds are typical of many transition metal compounds. In both the yellow potassium chromate (K2Cr04) and the orange potassium dichromate (K2Cr207), chromium has a 6+ oxidation number. 

CrOj dk. red H2Cr04 or [Cr02(0H)2] HyCryOy Ot [CryOjfOHly] chromic acid dichromic acid weakly acidic acidic K2Cr04 yellow KyCryOy orange potassium chromate potassium dichromate... 

Oxidation reaction with aqueous orange potassium... 

In this redox reaction, the orange potassium dichromate(VI) will turn green when it reacts with sodium sulfate(IV) in the presence of sulfuric(VI) acid. A redox reaction is one in which the oxidation states of atoms in substances are changed, indicating the presence of an oxidising or reducing agent (Chapter 7) in the unknown sample. For example, in this reaction ... 

Potassium nitrate is a white solid at room temperature. Other compounds containing potassium ion include orange potassium dichromate, KjCrjO, and purple potassium permanganate, KMn04. 

Turn a solution of potassium dichromatefVI) acidified with dilute sulphuric acid from orange to green. 

Liquid chlorine dioxide, ClOj, boils at 284 K to give an orange-yellow gas. A very reactive compound, it decomposes readily and violently into its constituents. It is a powerful oxidising agent which has recently found favour as a commercial oxidising agent and as a bleach for wood pulp and flour. In addition, it is used in water sterilisation where, unlike chlorine, it does not produce an unpleasant taste. It is produced when potassium chlorate(V) is treated with concentrated sulphuric acid, the reaction being essentially a disproportionation of chloric(V) acid ... 

If nickel(II) cyanide, Ni(CN)2, is dissolved in excess potassium cyanide, the orange-red complex salt K2Ni(CN)4. HjO can be crystallised out this contains the stable square-planar [Ni(CN)4] anion. 

To a cold aqueous solution of picric acid, add about an equal volume of dilute potassium cyanide solution. An orange coloration develops and rapidly darkens to a deep red. 

To obtain the free acid, dissolve the potassium salt in 50 ml. of cold water, filter the solution if a small undissolved residue remains, and then boil the clear solution gently whilst dilute sulphuric acid is added until the separation of the acid is complete. Cool the solution and filter off the pale orange-coloured crystals of the benzilic acid wash the crystals on the filter with some hot distilled water, drain well, and then dry in a desiccator. Yield of crude acid, 4 g. Recrystallise from benzene (about 50 ml.) to which a small quantity of animal charcoal has been added, filtering the boiling solution through a preheated funnel fitted w ith a fluted filter-paper, as the benzilic acid readily crystallises as the solution cools alternatively, recrystallise from much hot water. The benzilic acid is obtained as colourless crystals, m.p. 150°. 

Dissolve I drop of quinoline in 1 ml. of dil. HCl and add a few drops of a saturated solution of potassium dichromate. A copious orange-yellow precipitate of quinoline dichromate, (C,H7N)2 HjCrj07, is formed pyridine does not give a crystalline dichromate under these conditions. 

Lead antimonate [13510-89-9] (Naples yellow), Pb2(Sb0 2> mol wt 993.07, d = 6.58g/cm, is an orange-yeUow powder that is insoluble in water and dilute acids, but very slightly soluble in hydrochloric acid. Lead antimonates are modifiers for ferroelectric lead titanates, pigments in oil-base paints, and colorants for glasses and glazes (see Colorants for ceramics). They are made by the reaction of lead nitrate and potassium antimonate solutions, followed by concentration and crystallization. 

Detection of Bromine Vapor. Bromine vapor in air can be monitored by using an oxidant monitor instmment that sounds an alarm when a certain level is reached. An oxidant monitor operates on an amperometric principle. The bromine oxidizes potassium iodide in solution, producing an electrical output by depolarizing one sensor electrode. Detector tubes, usefiil for determining the level of respiratory protection required, contain (9-toluidine that produces a yellow-orange stain when reacted with bromine. These tubes and sample pumps are available through safety supply companies (54). The usefiil concentration range is 0.2—30 ppm. 

The primary Cr—O bonded species is cbromium (VT) oxide, CrO, which is better known as chromic acid [1115-74-5], the commercial and common name. This compound also has the aliases chromic trioxide and chromic acid anhydride and shows some similarity to SO. The crystals consist of infinite chains of vertex-shared CrO tetrahedra and are obtained as an orange-red precipitate from the addition of sulfuric acid to the potassium or sodium dichromate(VI). Completely dry CrO is very dark red to red purple, but the compound is deflquescent and even traces of water give the normal mby red color. Cbromium (VT) oxide is a very powerful oxidi2er and contact with oxidi2able organic compounds may cause fires or explosions. 

Benzyl Orange [4-(4-benzylaminophenylazo)benzenesulfonic acid potassium salt] [589-02-6] M 405.5, pKEst(i) <0, pKEst(2) 3.8. Crystd from H2O. 

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