Densities and Viscosities of Chromium Trioxide + Potassium Chromate + Potassium Dichromate + Water from (298.15 to 333.15) K

2008 ◽  
Vol 53 (3) ◽  
pp. 648-653 ◽  
Author(s):  
Ji-yan Wang ◽  
Fu-an Wang ◽  
Peng Zhang ◽  
Cheng-wei Li ◽  
Bao-zeng Ren
Keyword(s):  
Chromium Trioxide ◽  
Potassium Dichromate ◽  
Potassium Chromate

scholarly journals Polarization Studies on Inhibitory Effect of Chromates and Dichromates on Corrosion of Tin Coated Steel in 0.5M Monochloroacetic Acid

2008 ◽  
Vol 5 (2) ◽  
pp. 302-308
Author(s):  
Sangita Sharma ◽  
Kinnari H. Parikh ◽  
Mahesh V. Kadia ◽  
Falguni D. Thakkar ◽  
Dhara D. Patel
Keyword(s):  
Corrosion Behaviour ◽  
Potassium Dichromate ◽  
Corrosion Current ◽  
Inhibitory Effect ◽  
Open Circuit ◽  
Potassium Chromate ◽  
Monochloroacetic Acid ◽  
Sodium Chromate ◽  
Coated Steel ◽  
Sodium Dichromate

Chromates and Dichromates have been tested for its inhibitory effects towards tin coated steel in 0.5M monochloroacetic acid. The corrosion behaviour of potassium chromate, sodium chromate, potassium dichromate, sodium dichromate and ammonium dichromate was studied by polarization curves, Tafel parameters like Tafel slopes, extrapolation of cathodic Tafel line and intersection of cathodic and anodic line at open circuit potential in presence of inhibitors have been tabulated along with other electrochemical parameters and corrosion current have been calculated from Tafel lines. The efficiencies are calculated and compared reasonably well with those obtained from loss in weight data. All the inhibitors induce a significant increase of potential positive and direction accounts for cathodic polarization. The Icorrhas also been calculated and that accounts well for cathodic reactions in presence of chromates and dichromates as inhibitors.

CONTRIBUTION TO THE STUDY OF THE PRECIPITATION OF CHROMATES

1938 ◽  
Vol 16b (2) ◽  
pp. 37-45 ◽  
Author(s):  
P. E. Pelletier ◽  
L. Cloutier ◽  
Paul E. Gagnon
Keyword(s):  
Room Temperature ◽  
Chromium Trioxide ◽  
Potassium Chromate ◽  
Salt Solutions ◽  
Copper Salts ◽  
Metallic Salt

A study was made of the precipitation of the chromates of copper, cadmium, cobalt, zinc, and iron at room temperature. The concentration of the reacting metallic salt solutions was kept constant, and that of the potassium chromate solutions was varied regularly. Solutions were mixed in less than one-tenth of a second, and the rate of mixing was accurately determined. The ratio of oxide to chromium trioxide was found by analysis for chromium trioxide and the metal on the same portion of the precipitate. If the ratio remained constant with varying concentrations of reactants, a definite compound was indicated. The composition of the precipitates obtained with copper salts approached that of the normal chromate. Cadmium and cobaltous salts always gave normal chromates. Zinc and ferric salts yielded only basic mixtures.

scholarly journals Application of Inorganic Oxidants to the Spectrophotometric Determination of Ribavirin in Bulk and Capsules

2006 ◽  
Vol 89 (2) ◽  
pp. 341-351 ◽  
Author(s):  
Ibrahim A Darwish ◽  
Alaa S Khedr ◽  
Hassan F Askal ◽  
Ramadan M Mohamed
Keyword(s):  
Ammonium Sulfate ◽  
Acid Medium ◽  
Chromium Trioxide ◽  
Potassium Dichromate ◽  
Ammonium Molybdate ◽  
The Other ◽  
Potassium Iodate ◽  
Potassium Periodate ◽  
Spectrophotometric Methods

Abstract Eight spectrophotometric methods for determination of ribavirin have been developed and validated. These methods were based on the oxidation of the drug by different inorganic oxidants: ceric ammonium sulfate, potassium permanganate, ammonium molybdate, ammonium metavanidate, chromium trioxide, potassium dichromate, potassium iodate, and potassium periodate. The oxidation reactions were performed in perchloric acid medium for ceric ammonium sulfate and in sulfuric acid medium for the other reagents. With ceric ammonium sulfate and potassium permanganate, the concentration of ribavirin in its samples was determined by measuring the decrease in the absorption intensity of the colored reagents at 315 and 525 nm, respectively. With the other reagents, the concentration of ribavirin was determined by measuring the intensity of the developed colored reaction products at the wavelengths of maximum absorbance: 675, 780, 595, 595, 475, and 475 nm for reactions with ammonium molybdate, ammonium metavanidate, chromium trioxide, potassium dichromate, potassium iodate, and potassium periodate, respectively. Different variables affecting the reaction conditions were carefully studied and optimized. Under the optimum conditions, linear relationships with good correlation coefficients (0.99840.9998) were found between the absorbance readings and the concentrations of ribavirin in the range of 41400 g/mL. The molar absorptivities were correlated with the oxidation potential of the oxidants used. The precision of the methods were satisfactory; the values of relative standard deviation did not exceed 1.64%. The proposed methods were successfully applied to the analysis of ribavirin in pure drug material and capsules with good accuracy and precision; the recovery values were 99.2101.2 0.481.30%. The results obtained using the proposed spectrophotometric methods were comparable with those obtained with the official method stated in the United States Pharmacopeia.

Isolation and staining of wheat transfer cells

1978 ◽  
Vol 56 (16) ◽  
pp. 1992-1995 ◽  
Author(s):  
S.-Y. Zee
Keyword(s):  
Chromium Trioxide ◽  
Potassium Dichromate ◽  
Transfer Cells ◽  
Ammonium Dichromate ◽  
Basic Dyes ◽  
Nodal Tissue

Xylem and phloem transfer cells in the vegetative nodes of wheat, fixed in a mixture of 3% ammonium dichromate + 3% potassium dichromate and 20% formalin (1:1), could be easily separated from the nodal tissue using a mixture of 2% chromium trioxide + 8% H2SO4 + 3% HNO3 solution. After maceration and staining (with either acidic or basic dyes), the well organized protoplast and the weakly birefringent walls of the transfer cells could be seen clearly.

The reactions of the chromate, dichromate, and permanganate ions with 100% sulfuric acid and dilute oleum

1987 ◽  
Vol 65 (11) ◽  
pp. 2665-2669 ◽  
Author(s):  
R. J. Gillespie ◽  
R. Kapoor
Keyword(s):  
Sulfuric Acid ◽  
Absorption Spectra ◽  
Potassium Permanganate ◽  
Potassium Dichromate ◽  
Potassium Chromate

Solutions of potassium chromate and potassium dichromate in 100% sulfuric acid and dilute oleum have been investigated by cryoscopic and conductimetric methods. It is shown that they both react to give the compound CrO2(HSO4)2. The absorption spectra of solutions of potassium chromate and dichromate in 100% sulfuric acid are very similar to the spectra of species of the type CrO2X2. Potassium permanganate dissolves in 100% sulfuric acid to give green solutions which are shown to contain MnO3•SO4H. The formation of this compound has been further confirmed by conductimetric measurements in dilute oleum. The absorption spectra of these green solutions are also consistent with the formation of a species of the type MnO3X.

Untersuchungen über Isopolychromate

1968 ◽  
Vol 23 (9) ◽  
pp. 1137-1144 ◽  
Author(s):  
O. Glemser ◽  
W. Höltje ◽  
M. Stockburger
Keyword(s):  
Raman Spectroscopy ◽  
Absorption Spectrum ◽  
Raman Spectrum ◽  
Aqueous Solutions ◽  
Chromium Trioxide ◽  
Potassium Dichromate ◽  
The State ◽  
Laser Raman Spectroscopy ◽  
Laser Raman ◽  
Infra Red

The infra-red absorption spectrum and laser raman spectrum of crystalline potassium trichromate are reported and compared with the corresponding spectra of potassium dichromate. It is shown that the state of aggregation of acid and concentrated aqueous chromate solutions can be investigated by use of laser raman spectroscopy. Trichromate ions are found to exist in acid dichromate solutions having concentrations ≧ 3 M and acidity pH ≪ 0, and in aqueous solutions of chromium trioxide provided concenrations are ≧ 2 M.

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