• G S Deshmukh

      Articles written in Proceedings – Section A

    • Interaction of nitrous oxide, nitrogen and phosphorus under silent electric discharge

      G S Deshmukh Y D Kane

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      Interaction with phosphorus films of nitrous oxide, nitrogen and oxygen in silent discharge under fields due to potentials (V) of 50, 500 cycles and the high frequencies has been studied at various pressuresp. In agreement with a general finding due to Prof. Joshi,2, 3, 4 the change sets in above a minimum Vm and that both the currenti and the reaction rate at a given V depend upon V−Vm.p decreases progressively to zero, when the reaction terminates; this is characterised by a remarkably sudden drop of the correspondingi. Free O2 is not observed; NO occurs only at early stages. Two simultaneous changes (ia) and (ib), the former being the more rapid, followed by (ii) represent the reaction mechanismviz., N2O→N2+O (ia) N2O→N+NO (ib) NO→N+O (ii). The atomic products react with phosphorus immediately. Removal of molecular N2, from (ia) and that formed by recombination of N from (ib) and (ii) by phosphorus, is the longest stage. Phosphorus nitride is the chief product with both N2O and N2. The time-variation ofi is markedly synchronous with, but more pronounced than that ofp; and more helpful in revealing the stages of the reaction, suggested as a general proposition by Joshi.3 Interaction with oxygen produces a rise ofi in striking contrast with that with nitrogen.

    • Interaction of nitrogen and sulphur under silent electrical discharge: Production of a reverse change

      G S Deshmukh S Sirsikar

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      Results are given for the interaction of sulphur films with nitrogen at various initial pressuresp (2–15 cm. Hg) and excited in the range 3 to 11 kV (50 cycles). The occurrence of the reaction only above a minimum ‘threshold potential’ Vm and the dependence of its velocity, at a given V, on V−Vm are in accord with Joshi’s concept of the fundamental importance of Vm in discharge reactions.4, 5, 6 With a fresh film of sulphur,p andi decrease progressively, reach a minimum and increase again to a constant maximum stage almost synchronously on continued exposure to discharge. Thereversal ofp andi is more pronounced as V and 1/p are increased. The formation of sulphur nitride is observed. The time variation ofp andi suggest that the ‘clean-up’ of nitrogen is due to the formation of nitrogen tetrasulphide and/or adsorption complex of sulphur and nitrogen. The disappearance of the glow at the minimump stage and its non-observation during thereversal is attributed to the formation of a protective film of N4S4 or/and adsorption complex on the sulphur film under the discharge.

    • Production ofJoshi-effect in iodine vapour in electric discharge

      G S Deshmukh

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    • On the solubility of rare earth hydroxides in aqueous sodium potassium tartrate

      G S Deshmukh K V Nayak

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      The behaviour of rare earth hydroxides towards variously concentrated solutions of sodium potassium tartrates is studied. Their solubility varies in the order Ceiii>La; that of erbium, yttrium and ceric is, however, found to be almost negligible. This suggests a fairly rapid method of separation of rare earths (a) yttrium and erbium from (b) lanthanum and cerous salts; and the fractionation of (b).

    • A new volumetric method of cerium determination by thiocyanate

      G S Deshmukh

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      A new volumetric method for cerium determination, based on the reduction of ceric sulphate by potassium or ammonium thiocyanate added in excess and the determination of the excess by back-titration as in Volhard’s method is developed. One molecule of KCNS reacts with six molecules of Ce(SO4)2; the sulphur atom of the thiocyanate is oxidized to sulphate. Ce... and SO4″ ions in moderate quantities and the usual rare earth impurities in ceric sulphate do not affect the accuracy of the method. The possibility of using ceric sulphate in the determination of small quantities of thiocyanate and in argentometric titration is suggested.


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