Metal sulphate hydrazines

Bring a solution of 0.3 M Fe sulphate (560 mL) to 90 °C and add 240 mL of a solution 3.33 M in KOH and 0.27 M in KNO3 dropwise over a few minutes. Heat the suspension for 60 min with stirring, cool, wash and dry the black precipitate. It is essential that the entire preparation be carried out under an atmosphere of N2 and that all solutions be outgassed with N2 before use (David and Welch, 1956). To avoid any formation of Fe " oxides either hydrazine or metallic Fe can be added (Regazzoni et ak, 1981). 

Anhydrous hydrazine dssolves many salts, thus, 100 parts of solvent at 12-5°-13° dissolve 12-2 parts of sodium chloride 8 5, of potassium chloride 56-4, of potassium bromide 135-7, of potassium iodide 26-6, of sodium nitrate 21-7, of potassium nitrate and 814, of barium nitrate. The hydrazine seemed to unite with sodium chloride with a warm soln. of ammonium chloride, ammonia is evolved, and in the cold, there seems to be a state of equilibrium a complex salt seems to be formed with lead nitrate. An aq. soln. of hydrazine hydrate also dissolves a number of salts, potassium bromide and iodide, ammonium sulphate, potassium cyanide, barium nitrate, magnesium sulphate, etc. According to T. W. B. Welsh and H. J. Broderson, the solubility of the metal haloids seems to... 

The chemical properties o orthophosphoric add.—W. Muller-Erzbach21 has discussed the affinity of the metals for phosphoric acid. J. Thomsen found the avidity of a mol. of phosphoric acid for one of sodium hydroxide to be a quarter of the value of that for hydrochloric acid. The affinity of phosphoric acid for the bases is greater than that of carbonic acid, boric acid, phosphorous acid, and hypophosphorous acid. The catalytic action of phosphoric acid on the reaction between bromic and hydriodic acids has been studied by W. Ostwald on the reaction between iodic and sulphurous acids, by R. Hopke and A. Purgotti and L. Zanichelli on hydrazine sulphate, N2H4.H2S04. According to W. Ostwald, the velocity constant for the inversion of cane sugar by phosphoric acid is 6-21 when the value for hydrochloric acid is 100 and J. Spohr showed that the presence of neutral salts at 25° retards, or at 40° completely suppresses,the activity of phosphoric acid. 

Colloidal rhodium may also be prepared by reduction of pure rhodium salts with hydrazine hydrate. Traces of impurity prevent the formation of the hydrosol, which is very unstable. Addition of a protective colloid, such as a 1 per cent, solution of gum acacia, renders the hvdrosol stable, so much so that it admits of concentration over sulphuric acid in vacuo, yielding a dark brown solid mass of colloidal metal, containing 99-4 per cent, of rhodium, and almost completely soluble in water.5 Shaking the colloidal solution with barium sulphate or animal charcoal serves to coagulate the metal. 

Kemmerer.1 On the other hand, Keller and Smith, who consider that traces of palladium are lost by this method, determined the palladium content of the compound electrolytically, as also did Amberg 2 in two series of experiments, and Woernle. Moreover, Amberg made a series of determinations in which the reduction to metal was accomplished in solution with hydrazine sulphate, while Shinn 3 effected his reductions with ammonium formate. The results of these investigations are summarised in the following table ... 

Hydrazine sulphate (saturated) when added to a solution of diammine-argentate ions, forms finely divided silver metal, while gaseous nitrogen is evolving ... 

Hydrazine sulphate ready reduction in ammoniacal solution to metallic platinum, some of which is deposited as a mirror upon the sides of the tube. 

---