Manganous carbonate, precipitation

As an oxidant for manganous ion in acid solution, chlorate ion was found to be the most convenient. Manganous carbonate was dissolved in concentrated nitric acid, and sodium chlorate was added a few crystals at a time until complete oxidation had apparently taken place. The precipitate was allowed to settle then the entire mass was poured into a large volume of water and filtered. The residue was catalytically active at — 20°C. 

The removal of inorganic salts from reaction mixtures afforded by polymeric materials may be simply and effectively accomplished by dialysis,166 178 after decomposition of remaining periodate with ethylene glycol130 131 or butylene glycol. 161 170 Alternatively, the iodate and periodate ions may be removed as such, or after reduction to free iodine. The iodate and periodate ions have been effectively precipitated by means of sodium carbonate plus manganous sulfate,6 or by lead dithionate,191 barium chloride,24 192 193 strontium hydroxide194 202 or barium hydroxide,203 204 lead... 

Formic acid solution reacts as follows 11) with hydroxides, oxides, carbonates, to form formates, e g., sodium formate, calcium formate, and with alcohols to form eslers (2) with silver of ammonio-silver nitrate to form metallic silver (3) with ferric formate solution, upon heating, to form red precipitalc of basic ferric formate (4) with mercuric chloride solution to form mercurous chloride, white precipitate and (SI with permanganate lin the presence of dilute H-SOj) to form CO and manganous salt solution. Formic acid causes painful wounds when it ennies in contact with the skin. At IhO C. formic acid yields CO plus H . When sodium formate is heated in vacuum at 300°C. H- and sodium oxalate are formed. With concentrated ll.SOj heated, sodium formate, or other formate, or formic aeid. yields carbon monoxide gas plus water. Sodium formate is made by healing NaOH and carbon monoxide under pressure at 2I0 C. 

If no precipitate is obtained, the substance is largely free from heavy metals, and the sodium carbonate treatment may be omitted if more of the solution is required. Certain amphoteric elements may, however, be present in the sodium carbonate solution, e.g. Cu, Sn, Sb, As, Al, Cr, and Mn, dissolved in appreciable quantities manganates, permanganates, and chromates may also be present... 

Analytical Characters.—Manganous.—(1.) Potash, white ppt., turning brown. (2.) Alkaline carbonates, white ppts. (3.) Ammonium sulfhydrate, flesh-colored ppt., soluble in acids, sparingly soluble in excess of precipitant. (4.) Potassium ferrocyanid, faintly reddish-white ppt., in neutral solution soluble in HCl. (5.) Potassium cyanid, rose-colored ppt., forming brown solution with excess. 

The process of auto-oxidation-reduction is also used manganate ion is stable in alkaline solution, but not in neutral or acidic solution. The addition of any acid, even carbon dioxide (carbonic acid), to a manganate solution causes the production of permanganate ion and the precipitation of manganese dioxide ... 

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