Chromic acid s. Chromium trioxide

Chromic acid (s. a. Chromium trioxide) 31, 219 Chromium carbonyl compds. 

Chromic acid (s. a. (Chromium trioxide) 31, 219 Chromium s. a. Chromyl. Chromium(II) acetate 32, 520 Chromium carbonyl compds. 

Chromium oxide s. Chromium trioxide. Manganese-chromium-zinc oxide Chromium(ll) sulfate—cation exchange resin 14,137 Chromium trioxide s. Chromic acid... 

It is doubtful if hydrated chromium trioxide has been prepared in the solid state. H. Moissan 2 said that if an almost sat. aq. soln. of chromium trioxide be kept for several hrs. at about 90°, and then cooled below 0°, small red crystals of chromic acid, H2Cr04, collect on the walls of the containing vessel. This does not agree with J. J. Berzelius s observations, while F. Mylius and R. Funk, T. Costa, and E. Field were unable to confirm H. Moissan s observation. H. C. Jones showed that the f.p. of aq. soln. of chromium trioxide agreed with the assumption that the solvation for soln. with m mols of Cr03 per litre, can be represented by the mols of water in combination with a mol of CrOs ... 

The crystals are chromium trioxide, CrOs, not chromic acid, H2Cr04. The Shlubility of chromium trioxide in water was measured by R. Kremann who found that sat. soln. at d° contained S grms. of CrOs per 100 grms. of soln. 

I. Walz obtained some iodate by the action of chromic acid on iodine. H. S. Fry treated chromium trioxide with acetyl iodide and obtained only iodine. There was no evidence of the formation of chromyl iodide. 

C.9.1 Zinc and Zinc Alloys 150 mL ammonium hydroxide (NH4OH, sp gr 0.90) Reagent water to make 1000 mL followed by 50 g chromium trioxide (CrOj) 10 g silver nitrate (AgN03) Reagent water to make 1000 mL 15 to 20 s Boiling The silver nitrate should be dissolved in water and added to the boiling chromic acid to prevent excessive crystallization of silver chromate. The chromic acid must be sulfate free to avoid attack of the zinc base metail. 

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