Potassium chromium alum

Two solutions are prepared (a) 5 g. (0.01 mol) of potassium chromium alum is dissolved in 20 ml. of water and (b) 21 g. of sodium hydroxide (0.50 mol) and 10 g. of bigua-nide sulfate 2-hydratet is dissolved in 50 ml. of water. Solution b is heated to 75°, and solution a is added drop by drop with constant stirring. As each drop strikes the alkaline solution, there is a momentary formation of green chromium hydroxide which dissolves to form a dark red solution. As the reaction progresses, bright red, prismatic crystals separate from the solution. After all of solution a has been added, the mixture is cooled in ice water until no more solid separates. The crystals are filtered on a fritted-glass funnel and washed with 5 ml. of cold water. 

SYNS CHROME ALUM CHROME POTASH ALUM CHROMIC POTASSIUM SULFATE CHROMIC POTASSIUM SULPHATE CHROMIUM POTASSIUM SULFATE (1 1 2) CHROMIUM POTASSIUM SULPHATE CRYSTAL CHROME ALUM POTASSIUM CHROMIC SULPHATE POTASSIUM CHROMIUM ALUM POTASSIUM DISULPHATOCHROMATE(III) SULFURIC ACID, CHROMIUM (3+) POTASSIUM SALT (2 1 1)... 

Potassium Chromium Alum, Chrome Alum, KjSOj. Cr2(S04)3.24H20, first isolated by Mussin-Pusehin, is obtained by the reduction of a mixture of potassium dichromate and sulphuric acid by sulphurous acid, alcohol, oxalic acid, etc. ... 

Basicity chrome alum CCRIS 7532 Chrome alum Chrome potash alum Chromic potassium sulfate Chromic potassium sulphate Chromium potassium bis(sulphate) Chromium potassium sulfate (1 1 2) Chromium potassium sulfate (CrK(S04)2) Chromium potassium sulphate Chromium(lll) potassium sulfate Crystal Chrome Alum EINECS 233401-6 Potassium chromic sulfate Potassium chromic sulphate Potassium chromium alum Potassium chromium disulfate (KCr(S04)2) Potassium disulphatochromate (III) Sulfuric acid, chromium(3 ) potassium salt (2 1 1). Mordant for dyeing fabrics uniformly [dodecahydratej mp = 89° d = 1.83 soluble in 4 parts H2O. 

Materials Potassium aluminium alum, potassium chromium alum. 

Directions (a) Dissolve 16 grams of potassium aluminium alum in 100 c.c. of hot water, filter if necessary, and cool the solution to room temperature in running water. Shake occasionally for five minutes 8 grams of finely powdered potassium chromium alum with 100 c.c. of water at about 30°. The temperature should not be allowed to go higher than 35° in order to prevent the change of the chromium salt to the green modification. Filter the solution. In four beakers place the following (1) 40 c.c. of the solution of aluminium alum and 10 c.c. of the chromium alum, (2) 20 c.c. of the former and 10 c.c. of the latter, (3) the rest of the solution of the former and (4) the rest of the solution of the latter. 

Potassium Chromium Alum KjCrj(SOJ. 24HjO 12.51 24.39 o o44i Tellurium Chromium Alum TejCr2(SO ). 24HjO 10.41 16.38 0.021a... 

If more than simple atoms are bound to a central atom, then the coordination number still refers to the number of near neighbors. For example, in solid potassium chrome alum, KCr(S04)2- 12H20, and also in its fresh aqueous solutions, the chromium-containing cation is... 

Probably the most common compound of +3 chromium is potassium chrome alum, KCr(SOi)r 12H20. We know that the twelve water molecules are distributed equally, six around Cr+a and six around K+. Potassium chrome alum is just one example of the general class of solids called alums which have a 4-1 ion, a +3 ion, two sulfates, and twelve molecules of water. In the dyeing industry chrome alum is used for fixing dyes to fabrics. 

Gamer and Jennings [431] studied nucleation during the dehydration of potassium and ammonium chromium alums. Detailed kinetic measurements were made for the relatively enhanced rate of nucleation which followed admission of water vapour to the solid after a period of vacuum nucleation. This catalytic effect of water vapour is ascribed to its participation in the reorganization of the lattice which had collapsed during previous treatment in vacuum. 

Filter off the formed crystals and dry them on filter paper. Choose a well formed crystal of the alum, fasten it with the aid of a thin thread or hair to a glass rod and lower it into the mother liquor. Watch how the crystal grows several days. Examine the shape of the chromium potassium alum crystals under a microscope and compare it with that of potassium aluminium alum crystals. What will happen if crystals of potassium aluminium alum are lowered into a saturated solution of chromium potassium alum. 

One hundred grams of very finely powdered potassium chromium (III) sulfate (chrome alum) are mixed in a flask... 

Synonyms Chrome alum, Chromium and potassium sulfate, Potassium chromium sulfate. Appearance Dark violet-red crystals (ruby red by transmitted light) or light violet powder. Uses Preparation of chrome alum fixing bath as hardening agent for gelatin. 

Salmonella typhimurium TA100, TA1535 TA98, TA1537, TA1538 Reverse mutations Base pair substitutions Frame shift mutations - - De Flora 1981 Petrilli and De Flora 1978b Chromium trichloride hexahydrate, chromium nitrite, monohydrate, chromium potassium sulfate, chromium acetate, neochromium, chromium alum, chromite... 

Chromium in its Compounds is sometimes metallic and sometimes non-metallic toward the other components. Thus, in chromium trioxide, CrOg, the anhydride of the hypothetical chromic acid, H2Cr04, chromium acts as a non-metal, just like sulphur in sulphuric acid hence in chromates the chromium is acidic, or non-metallic, in its chemical relations with the other elements. In chromic compounds, however, chromium acts as a metal. Thus chromium hydroxide, Cr(OH)3, is analogous to aluminium hydroxide chrome alum is potassium chromium sulphate, and is analogous to aluminium alum. The two classes pass into each other by appropriate operations,... 

Arrhenius parameters for the dehydrations of ammonium and potassium aliuninium alums [38] were in agreement with the Polanyi-Wigner equation. Comparisons of the shapes of nuclei on different crystal surfaces indicated that reaction proceeds along (100) planes. The observed decrease of the rate in water vapour is attributed to the blocking of pores by adsorbed molecules. No intranuclear cracking was apparent and the product-reactant boimdaries became irregular because of the influence of water on reorganization of the product phase. The appearance of these nuclei contrasted markedly with those in mixed potassium chromium/aluminium alums, where there is an approximately concentric structure. 

Crystals of potassium chrome-alum, potassium chromium sulphate, or potassium... 

Fig. 81.—Composition of Solution and Solid Mixtures of Potassium Chromium and Potassium Aluminium Alums.

Fig. 82.—Vapour Pressures of Mixtures of Potassium Chromium in Potassium Aluminium Alums.

Potassium chrome alum Potassium chromium sulfate... 

Potassium chromate (VI) Potassium chromate, yellow. See Potassium chromate Potassium chrome alum Potassium chromium sulfate. See Chromium potassium sulfate Potassium citrate... 

Alum, chrome (see Chromium potassium sulfate) Alum, potassium (see Aluminum potassium sulfate) Alum, sodium (see Aluminum sodium sulfate)... 

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