On account of the strong alkaline solution, the original color produced by the phenolphthalein is very faint, but this slowly increases until it becomes deep just before the acid point is reached.
It is advisable to titrate the crude anthranilic acid with standard alkali and phenolphthalein before starting the experiment.
A few drops of phenolphthalein solution are added and sulfur dioxide passed in, first until an acid reaction is indicated and then for two or three minutes longer.
Then boil for two minutes, neutralize exactly with dilute acetic acid (use phenolphthalein as the indicator).
After the addition of phenolphthalein the acid is titrated, and the amount used calculated into oleic acid.
A drop of phenolphthalein is now added, a little water, and the acidity determined by titration with deci-normal baryta solution, and the baryta solution taken calculated as oleic acid.
The liquid is then filtered into a large flask, the residue on the filter is well washed with water, the filtrate quite cooled, phenolphthalein is added and the fluid exactly neutralised with a dilute (2 to 3 per cent.
Titrate with N/20 NaOH, using phenolphthalein as an indicator; make titrations at same time from blank.
Phenolphthalein as shown above is not a good indicator for this purpose.
Most saprophytic organisms and many parasitic ones grow within a wide range of H ion concentration so that titration withphenolphthalein gives sufficient accuracy for media for such organisms.
Normally fresh milk is sufficiently acid in reaction when tested to phenolphthalein to permit rennet to act, but the rate of action increases rapidly with the development of acid.
Milk as drawn shows a measurable acidity when titrated to phenolphthaleinwith normal sodium hydroxide.
As an indicator, a 1 per cent solution of phenolphthalein in 95 per cent alcohol is commonly used.
Transfer the precipitate and filter to the beaker, or precipitating vessel, dissolve the precipitate in a small excess of the standard alkali, add a few drops of phenolphthalein solution, and titrate with the standard acid.
Titrate the distillate with N/10 alkali, using phenolphthalein as an indicator.
Oh, it contains somephenolphthalein and a salicylate, but I have forgotten the exact proportions.
Since phenolphthalein occurs in the form of an insoluble and tasteless powder there is no reason why special pharmaceutical preparations of it should be placed on the market.
Phenolphthalein itself has certain pretty well defined properties, but when a little of some other drug has been added wonderful therapeutic possibilities are claimed for the combination.
At the time phenolphthalein was beginning to be exploited in this country The Journal[116] suggested that physicians who wished to try the remedy should prescribe it under its own name and not under fancy, coined names.
The exploitation of phenolphthalein in this way gives opportunity to the manufacturers to make all sorts of strong claims, some of them directly contradictory, for their preparations.
Phecolax contains, in addition to the ingredients of Phecolates, phenolphthalein and cascarin, of each one-half grain.
Two drops of phenolphthalein were added, and the solution titrated with normal hydrochloric acid.
The organic compound phenolphthalein has been known for a long time and has been widely used as an indicator.
It is undoubtedly true, however, as we have previously stated, thatphenolphthalein is worthy of a trial.
It may be employed with some of the stronger organic acids, but the use of phenolphthalein is to be preferred.
Of the common indicators methyl orange is the most sensitive toward alkalies and phenolphthalein toward acids; the others occupy intermediate positions.
Add two drops of phenolphthalein solution, and run in alkali from the burette until the solution is pink; add acid from the other burette until the pink is just destroyed, and then add 0.
In the following discussion of the principles underlying the behavior of the indicators as a class, methyl orange and phenolphthalein will be taken as types.
Owing to the carelessness of the analyst's assistant, the sodium hydroxide solution was used with phenolphthalein as an indicator in cold solution in making the analyses.
The sample was titrated with hydrochloric acid until the pink of phenolphthalein disappeared, and on the addition of methyl orange the solution was colored pink.
N hydrochloric acid, using phenolphthalein in cold solution as an indicator and becomes colorless after the addition of 48.
On adding phenolphthalein to a solution of the substance, it gave no color to the solution.
After finding the free hydrochloric acid as just described, add four drops phenolphthalein solution, and continue the titration.
The amount of lactic acid or “loosely combined HCl” present in Lactopeptine is very small, since the total acid which may be titrated by sodium hydroxid and phenolphthalein is measured by 0.
As for phenolphthalein, which is credited with purely laxative properties, we are at a loss to see any bearing in the remark that phenolphthalein was popularized by nostrum makers.
The Laboratory further reported that they contain phenolphthalein and acetanilid.
The properties of phenolphthalein are not in the least influenced by the manner of its introduction, as Messrs.
Phenolphthalein was popularized by nostrum makers; and while it has some therapeutic value, this has been greatly overestimated, and it should be used only in amounts deemed necessary for each patient, preferably alone.
We cannot see that the physician’s or chemist’s estimate of phenolphthalein, its properties and uses, can be in the least degree influenced one way or the other by the statement that “phenolphthalein has been popularized by nostrum makers.
It is the combination of holadin, bile salts, sodium succinate and phenolphthalein to which objection is made.
The diluted solution is acid in reaction toward litmus and phenolphthalein and alkaline toward methyl orange.
If borax is present the carbon dioxide is boiled off after neutralizing exactly to methyl orange; cool, add mannite and phenolphthalein and titrate the boric acid with standard alkali.
Dissolve the residue in neutral alcohol and titrate with standard alkali using phenolphthalein as an indicator.
The solution is then neutralized with alcoholic sodium hydroxide, usingphenolphthalein as an indicator.
The mixture of fat and neutralized alcohol is then heated to boiling and titrated with tenth normal alkali solution, usingphenolphthalein as an indicator.
Cool and titrate with the N/2 hydrochloric acid, using phenolphthalein as an indicator.
Add phenolphthaleinto the filtrate and titrate with N/10 acid and calculate the per cent.
Methyl orange Red Yellow Very slightly acid Phenolphthalein Colorless Red Acid Litmus Red Blue Acid It may be further stated that methyl orange at the neutral point is orange in color.
To determine the alkali in the sample, 10 cubic centimeters are pipetted into a beaker, a little distilled water added, then 3 or 4 drops of phenolphthalein indicator.
Samples are taken at this time, cooled and tested by alcoholic phenolphthalein solution.
Because of the large quantity of water present, phenolphthalein is unsatisfactory, as dissociation of the soap may show a pink indication in spite of the fact the mass is on the acid side.
Test a freshly cut surface of the soap with a few drops of an alcoholic phenolphthalein solution.
The materials needed are: One glass pitcher, filled with water, four glass tumblers, an acid, an alkali and some phenolphthalein solution which can be obtained from your local druggist.
Mix the phenolphthalein with the alcoholic solution of saccharin (in a hot mortar if in a hurry), and permit the alcohol to evaporate.
Sample of filtered meat extract or nutrient gelatine to which phenolphthalein has been added.
We will take two jars containing solution of monocarbonate of soda, and in the first we will put some phenolphthalein solution, and in the second, some litmus tincture.
The presence of this free or excess alkali can be at once detected by rubbing a littlephenolphthalein solution on to the freshly-cut surface of a piece of soap; if free alkali be present, a red colour will be produced.
We have, therefore, in bicarbonate of soda a salt which behaves as an acid to phenolphthalein and as an alkali to litmus.
The above list will hopefully give you a few useful examples demonstrating the appropriate usage of "phenolphthalein" in a variety of sentences. We hope that you will now be able to make sentences using this word.
