United States or Bangladesh ? Vote for the TOP Country of the Week !
This cautious removal of solution does not seriously affect the accuracy of the determination, as it will be noted that the volume of the titrated solution is about 200 cc. and the portions removed are very small.
Drops of the indicator solution are placed upon a glazed porcelain tile, or upon white cardboard which has been coated with paraffin to render it waterproof, and drops of the titrated solution are transferred to the indicator on the end of a stirring rod.
From the weight of the latter the arsenic sulphide is calculated. As a less accurate but more rapid method, the ammoniacal solution of arsenic sulphide is cautiously neutralized with pure dilute nitric acid and considerably diluted. It is then titrated with decinormal silver nitrate till a drop of the solution is turned brown with neutral chromate.
It is then titrated back with decinormal soda; from this is now readily deducted the amount of carbonic acid, and from that the MnO , holding in view that 44 parts of carbonic acid is equivalent to 43.5 of MnO or 98.87 per cent, and that 1 c.c. of the N/10 baryta solution is equivalent to 0.0022 grm. of CO .
!Method B! !Oxalate Standards! PROCEDURE. Weigh out two portions of pure sodium oxalate of 0.25-0.3 gram each into beakers of about 600 cc. capacity. Make a blank test with 20 cc. of manganous sulphate solution and a volume of distilled water equal to that of the titrated solution to determine the volume of the permanganate solution required to produce a very slight pink.
Sulphide sulphur was determined in a sample of reduced barium sulphate by the evolution method, in which the sulphur was evolved as hydrogen sulphide and was passed into CdCl solution, the acidified precipitate being titrated with iodine and thiosulphate. Sample, 5.076 grams; cc. I = 20.83; cc. Na S O = 12.37; 43.45 cc. Na S O = 43.42 cc. I ; 8.06 cc. KMnO = 44.66 cc. Na S O ; 28.87 cc.
Both potassium bromate and cupric salts in solution will liberate iodine from an iodide, which is then titrated with the thiosulphate solution. Two methods for the direct standardization of the sodium thiosulphate solution are here described, and one for the direct standardization of the iodine solution. !Method A!
It was solid at 9° C., and sufficiently soft to flow at 12° C., but did not entirely liquefy under 22° C. To test its neutralizing power, 0.9575 gramme dissolved in alcohol was titrated with decinormal alkali; it required 34.05 c.c.
As in dissolving in hydrochloric acid and oxidizing with nitric acid the solution ought to be twice tested for protoxide of iron, even although at the first test none can be discovered. The silica is taken upon a filter, dried, ignited, and weighed. The filtrate is treated with bicarbonate of soda, and titrated with chameleon solution in the way described above. By NELSON H. DARTON.
One gram of an oxide of iron is fused with potassium acid sulphate and the fusion dissolved in acid. The iron is reduced with stannous chloride, mercuric chloride is added, and the iron titrated with a normal K Cr O solution. 12.94 cc. were used. What is the formula of the oxide, FeO, Fe O , or Fe O ? !Answer!: Fe O . !Answer!: Monovalent.
Word Of The Day