Qualitative analysis / by William Briggs and R.W. Stewart.

  • William Briggs
Date:
1913
Catalogue details

Licence: Public Domain Mark

Credit: Qualitative analysis / by William Briggs and R.W. Stewart. Source: Wellcome Collection.

    62/180 (page 46)
    mass is a mixture of potassium and sodium manganates, K2Mn04 and Na2Mn04. If the mixture is treated with a small quantity of water it forms a deep green solution of the manganates. Excess of water causes the colour of the solution to change to pale pink, the manganates being converted partly into perman¬ ganates (KMn04, NaMn04), and partly into hydrated manganic oxide, Mn203, H20. 8 K2Mn04 + 6 H20 = 6 KMn04 + Mn203, H20 -1- 10 KOH. The permanganates cause the pink colour; the Mn203, H20 falls as a brown precipitate. The conversion of manganates into permanganates is also readily brought about by the action of an acid (even carbonic acid). 8 K2Mn04 + 5 C02 + H20 = 6 KMn04 + Mn20B, H20 + 5 k2co3 8 K2Mn04 + 5 H2S04 = 6 KMn04 + Mn203, H20 + 5 K2S04 + 4 H20. 5. In the outer flame the borax bead is coloured amethyst when cold. In the inner flame the bead becomes nearly colourless. The most important salts of manganese are manganous sulphate, MnS04, and manganous chloride, MnCl2. Of these the sulphate is the more commonly met with. The manganic salts are very unstable. ZINC, Zn. Solution—Zinc Sulphate, ZnS04. 1. Ammonium sulphide, (NH4)2S, gives a white pre¬ cipitate of zinc sulphide, ZnS. ZnS04 + (NH4)2S = ZnS + (NH4)2S04. The precipitate is soluble in dilute mineral acids but not in acetic acid. [Distinction from MnJ\