Zinc powder - sodium carbonate method

Zinc powder sodium carbonate method for detection of elements, 1043 -1045 ... 

One method of preparing sulphlnic acids has already been described (diazo reaction. Section IV,65). Reduction of a sulphonyl chloride with zinc powder and water affords the zinc salt of the sulphinic acid, converted by sodium carbonate to the sodium salt (in which form it is conveniently isolated), and by hydrochloric acid into the somewhat unstable sulphinic acid, for example ... 

When an organic compound is heated with a mixture of zinc powder and sodium carbonate, the nitrogen and halogens are converted into sodium cyanide and sodium hahdes respectively, and the sulphur into zinc sulphide (insoluble in water). The sodium cyanide and sodium hahdes are extracted with water and detected as in Lassaigne s method, whilst the zinc sulphide in the residue is decomposed with dilute acid and the hydrogen sulphide is identified with sodium plumbite or lead acetate paper. The test for nitrogen is thus not affected by the presence of sulphur this constitutes an advantage of the method. 

There are several other methods to reduce diselenides, selenocyanates, and elemental selenium. For example, sodium hydroxymethanesulfinate (rongalite) [26], carbon monoxide [27a], zinc powder [27b],hypophosphorous acid (H3PO2) [28], and sodium hydroxide (NaOH) under phase-transfer conditions [29] have been used to prepare nucleophilic selenium species. 

Zhang and Li [42] prepared ZnO nanoparticles by precipitation transformation method. Solution of zinc sulfate was reacted with sodium carbonate solution with vigorous stirring. To this, NaOH solution was added dropwise. The reaction was performed at temperatures from 25 to 70 °C. Washing, filtration and drying followed to obtain powder ZnO nanoparticles. Zn5(C03)2(0H)6 was formed as intermediate and phase transformation in presence of NaOH solution led to formation ZnO... 

This is a complex compound of aluminium and sodium silicate and sodium sulphide. The typical and most common ultramarine is blue ultramarine, which forms a very fine powder (microscopically crystalline) of a pure blue, reddish blue or greenish blue colour according to the proportions of the components and the method of preparation ultramarines of other tints, especially green and violet ultramarines, are also made. Ultra-marine may be adulterated with gypsum, chalk, clay, heavy spar, zinc white and magnesium carbonate and may also be mixed with glycerine and glucose. 

---