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Run in the thiocyanate solution from a burette, with constant stirring, allowing the precipitate to settle occasionally to obtain an exact recognition of the end-point, until a faint red tinge can be detected in the solution. From the data obtained, calculate the relation of the thiocyanate solution to the normal.
In such cases, however, the knowledge of the approximate amount to be required should never be allowed to influence the judgment regarding the actual end-point. The strength or value of a solution for a specific reaction is determined by a procedure called !Standardization!, in which the solution is brought into reaction with a definite weight of a substance of known purity.
It has been noted above that the color change does not occur exactly at theoretical neutrality, from which it follows that no two indicators will show exactly the same end-point when acids and alkalis are brought together. It is plain, therefore, that the same indicator must be employed for both standardization and analysis, and that, if this is done, accurate results are obtainable.
Just as an acid solution was the principal reagent in alkalimetry, and the alkali solution used only to make certain of the end-point, the solution of the oxidizing agent is the principal reagent for the titration of substances exerting a reducing action.
The student is again reminded that variations in temperature of volumetric solutions must be carefully noted, and care should always be taken that no source of heat is sufficiently near the solutions to raise the temperature during use. It is then possible to run in rapidly approximately the required amount, after which it is only necessary to determine the end-point slowly and with accuracy.
The process whereby a !standard solution! is brought into reaction is called !titration!, and the point at which the reaction is exactly completed is called the !end-point!. The !indicator! should show the !end-point! of the !titration!. The volume of the standard solution used then furnishes the measure of the substance to be determined as truly as if that substance had been separated and weighed.
If this last previous test shows a blue tint in comparison with the fresh mixture, the end-point has not been reached; if no difference can be noted the reaction is complete. Should the end-point be overstepped, a little more of the ferrous solution may be added and the end-point definitely fixed.
Add 10 cc. of dilute sulphuric acid and titrate to a faint pink with the permanganate solution, adding it directly to the contents of the vacuum flask. Should the end-point be overstepped, the ferrous sulphate solution may be added. From the volume of the solution required to oxidize the iron in the wire, calculate the relation to the normal of the permanganate solution.
But the killer never stopped to figure out the ultimate end-point of his schemes. He worked like the very devil to convince Snookums that it would be all right to kill me without ever once considering whether Snookums would do it or not. He then drugged Mellon's wine, not knowing whether Mellon would try to kill me or someone else or anyone at all, for that matter.
The courtroom was thronged with friends of the dead physician-dentist, who not only is reported to be of a wealthy family of Bogota, Colombia, but generally is credited with many charitable works in the uptown Spanish colony here." The persistence of the thymus after adolescence makes for an arrest of masculinization or feminization, the end-point arrived at by the processes of puberty.
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