• R P Singh

      Articles written in Proceedings – Section A

    • Spectrophotometric determination of molybdenum with alloxantin

      Yag Dutt R P Singh

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      Alloxantin gives a deep yellowish-red colour with molybdates in aqueous solution. This colour reaction has been investigated and utilised for spectrophotometric determination of molybdenum. The colour has maximum intensity between pH range 3·3–3·9. It obeys Beer’s law at 400 mµ between the concentration limits of 0–25 p.p.m. of molybdenum. Molybdenum in concentration of 10 p.p.m. can be accurately estimated without any interference from 100 p.p.m. of tungsten present as tungstate and 500 p.p.m. of iron present as Fe++. The interference due to a number of other cations and anions has also been investigated.

    • Spectrophotometric determination of thorium using chrysin

      Mohan Katyal R P Singh

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      Chrysin forms a yellow coloured complex with thorium. This colour reaction has been investigated and utilised for spectrophotometric determination of thorium. The colour has maximum intensity at pH 2·8. It obeys Beer-Lambert’s law at 380 mµ between the concentration limits of 2 and 36 p.p.m. of thorium. The molar composition of the complex has been found to be 1:1.

    • Determination of some cations by high frequency titration technique using potassium chromate as precipitant

      A N Kumar R P Singh

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      Estimations of lead, barium, thallium and silver have been carried out in aqueous or ethanol-water media using a 30 Mc. unit. It has been found that lead and barium can be estimated by both direct and reverse titrations in aqueous medium. In case of silver and thallium (I), the addition of an equal volume of ethanol or methanol to the solution to be titrated was found essential for accuracy and reproducibility. Limits of tolerance for some ionic constituents which are frequently associated with these cations have also been determined. Thallium has been estimated by both direct as well as reverse titrations, but in case of silver, reverse titrations gave low results. The method requires much less time for the estimations as compared to other methods and the results fall within the ordinary limits of accuracy required.

    • Spectrophotometric determination of zirconium and other colour reactions by galangin

      Mohan Katyal R P Singh

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      The spectrophotometric determination of zirconium is described, based on the formation of a yellow coloured complex between zirconium and galangin. Maximum absorption by the reaction product only at one specific wavelength (410 mµ) in the acidity range of 0·5 N-HCl to pH 4·5, suggests the formation of only one complex. The complex, not extractable by usual organic solvents, has been studied in 40% alcoholic medium. It obeys Beer’s law from 1 to 6 p.p.m. of metal ion concentration and contains the two components in the molar ratio of 1:1. The effect of the reagent on other ions has been qualitatively studied. Also, the effect of foreign ions on the complex has been investigated.

    • Studies onO-Vanillinoxime as an analytical reagent - Part II. Gravimetric determination of copper and nickel and their separation from other metals

      D P Goel K C Trikha R P Singh

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      o-Vanillinoxime has now been used for the gravimetric determination of copper and nickel alone and in presence of many foreign ions. Copper can be estimated in presence of appreciable amounts of cadmium, zinc, cobalt and lead. The interference due to iron (III), antimony (III), bismuth (III) and tin (II) can be removed by suitable masking agents. Determination of copper and nickel in presence of each other has also been carried out.

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