Lanthanum nitrate test

Acetates may be detected by formation of foul-smelling cacodyl (poisonous) on heating with dry arsenic tiioxide. Other tests for acetate are the lanthanum nitrate test in which a blue or bluish-brown ring forms... 

Lanthanum nitrate test Treat 0-5 ml of the acetate solution with 0-5 ml OTm lanthanum nitrate solution, add 0-5 ml iodine solution and a few drops of dilute ammonia solution, and heat slowly to the boiling point. A blue colour is produced this is probably due to the adsorption of the iodine by the basic lanthanum acetate. This reaction provides an extremely sensitive test for an acetate. 

Lanthanum nitrate test treat 0.5 ml of the acetate solution with 0.5 ml... 

Lanthanum nitrate test (for acetic and propionic acids). Mix equal volumes of 5 % aqueous lanthanum nitrate, iodine solution and the solution of the substance. Add a few drops of dilute ammonium hydroxide solution, and heat slowly to boiling. The presence of acetic or propionic acid is indicated by the appearance of a blue colour. Sulphates interfere with the test. 

Lanthanum nitrate test forAcem/c In the pyrolysis test, insert into the mouth of the tube a cotton plug moistened with water. Remove the. cotton plug after 4—5 minutes, wash it with 1-2 ml distilled water, collect tlie washings in a test tube and add... 

PVAc gives a positive (deep blue colour) Lanthanum nitrate test (p.l88) for acetate. 

To about 15 mg in a test-tube, add 3 drops of phosphoric acid and close the tube with a stopper through which passes a smaller test-tube filled with water, and on the outside of which hangs a drop of lanthanum nitrate solution. Heat in a water-bath for 5 minutes (or if necessary bring slowly to the boil over a flame). Mix the drop of lanthanum nitrate solution with 1 drop of 0.02 N iodine on a white tile, and place 1 drop of dilute ammonia solution at the edge of the mixture. A blue color slowly appears at the junction of the two liquids indicating the presence of an acetyl group. 

The spot-test technique is as follows. Mix a drop of the test solution on a spot plate with a drop of OTm lanthanum nitrate solution and a drop of 0-005m iodine. Add a drop of m ammonia solution. Within a few minutes a blue to blue-brown ring will develop round the drop of ammonia solution. 

The procedure is simple successively add to the test solution 0.25 ml of lanthanum nitrate solution R, 0.1 ml of 0.05 M iodine, and 0.05 ml of dilute ammonia R2. When the mixture is heated until boiling, the formation of a blue precipitate or a blue coloration of the solution indicates a positive reaction. 

If lanthanum nitrate and ammonia are added to the test solution without iodine being present, a white precipitate of basic lanthanum nitrate develops. The precipitation initiates slowly at room temperature but is speeded up by heating. This precipitate will, in the presence of acetate ions, form a complex with iodine that can have the form of a blue solution or a blue precipitate. 

In a test tube about 180 mm long and 18 mm in external diameter, about 15 mg of the substance to be examined, or the prescribed quantity, is placed and 0.15 ml of phosphoric acid R is added. The tube is closed with a stopper through which passes a small test tube about 100 mm long and 10 mm in external diameter containing water R to act as a condenser. On the outside of the smaller tube, hang a drop of lanthanum nitrate solution R. Except for substances hydrolyzable only with difficulty, place the apparatus in a water-bath for 5 min and then take out the smaller tube. The drop is removed and mixed with 0.05 ml of 0.01 M iodine on a tile. At the edge, 0.05 ml of dilute ammonia R2 is added. After 1 to 2 min, a blue color develops at the junction of the two drops the color intensifies and persists for a short time. For substances hydrolyzable only with difficulty, heat the mixture slowly to boiling over an open flame and then proceed as prescribed above. 

Polymers containing vinyl acetate can be recognized by the fact that they produce acetic acid on thermal decomposition. Cellulose acetate behaves in a similar fashion. To test this, pyrolyze a small amount of sample and catch the vapors on water-moistened cotton. Then wash the cotton with some water and collect the liquid in a test tube. Add 3-4 drops of a 5 % aqueous lanthanum nitrate solution, 1 drop 0.1 Niodine solution, and 1 -2 drops... 

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We took advantage of the dispersibility of Pd Ce02 core-shell structures to deposit them into the porous scaffold of SOFC materials as anode catalysts in order to enhance the thermal stability of these materials. The porous scaffolds were composed of yttrium-stabilized zirconia (YSZ) covered with a film of the conductive oxide lanthanum strontium chromium manganite (LSCM). For comparison of the activity and thermal stability, we prepared other electrodes that were identical except that the catalyst was simply Pd (from Pd(II) nitrate) in one case and a mixture of Pd and CeOg (from Pd(II) and Ce(III) nitrate salts) in the other. All the samples were first calcined at 700 °G to remove any by-products and to stabilize the materials. Then, accelerated aging tests were performed by calcining the samples at 900 °C for 2 hours. Initially we tested all the formulations in symmetric cells, e.g. cells where the anode and cathode materials are the same. The corresponding Nyquist plots are shown in Fig. 7.12(a). 

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