J u l y , 1914
T H E JOl'RS=IL OF I N D C S T R I A L A N D ENGINEERING CHEMISTRY
gases evolved from t h e springs, t h e activity being entirely due t o t h e presence of radium emanation. I n order t o obtain a q u F : i itative result on t h e latter: a definite \-olume of t h e gas was collected in a n inverted graduated bottle. After noting t h e volume: t h e t e m perature a n d pressure, this gas was introduced into t h e electroscope a n d readings a t once made. T h e necessary correction for t h e increase in activity obtained a t t h e e n d of three hours was made as i t II-X not possible under field cond;tions t o wait for :his maxim u m activity t o be attained. In order t o get t h e activity of t h e n-ater;, samples were collected a t t h e springs a t a point nearest t o t h e source of supply. T h e bottles were hermetically sealed a n d shipped to t h e laboratory in ST'ashington by express. T h e y were t h e n boiled in t h e a p p a r a t u s designed by Schlundt a n d IIoorel a n d t h e evolved gases cont.aining t h e radium emanation n e r e introduced into a standardized elecposcope. On account of t h e large amount of carbon dioxide contained i n some of t h e waters i t was found advisable t o a d d a sufficient a m o u n t of c. P . sodium hydroxide before boiling. I n order t o differentiate between t h e activity due t o radium salts in solution a n d t h a t due t o dissolved ernanation, samples of some of t h e waters were treated with c. P. hydrochloric acid, boiled for fifteen minutes a n d t h e n sealed i n flasks a n d allowed t o s t a n d for a month. At t h e end of this period t h e y x e r e boiled in t h e usual way a n d from t h e activity obtained i t was possible t o calculate t h e a m o u n t of radium salts in solution. Samples of t h e (deposits from some of t h e springs were also collected a n d fused with sodium carbonate according t o t h e method of S t r u t t . ? Column 2 in t h e table of results gives t h e activity per liter a t s t a n d a r d temperature a n d pressure, of t h e gases evolved t h e springs; Column 3 gives t h e total activity per liter of t h e water, a n d Column 4 t h e activity per liter of t h e water due t o dissolved radium. Column j shows t h e activity of t h e material deposited either in or just around t h e outlet of t h e spring.
9
WATER DEPOSIT GAS Radium Radium Radium Tempera- per liter per liter per gram G r a m Gram X 10-11 Gram ture 0 c. x10-11 c___-. 10-11 SPRING 1 2 3 4 5 EmDeror.. . . . . . . . . . . 9.7 22.1 7.0 6 8 .. Peerless, . . . . . . . . . . . . . . 6.0 ... New red. . . . . . . . . . . . 1 o : o 8:O 4.3 ... Hathorn h-0, l . . . . . . . . . 10.2 4.2 7&:9 21.3 14.2 Coesa. . . . . . . . . . . . . . ... 7.9 9.7 10.2 8.1 Hathorn A-0. 2 . . . . . . 16.1 9.9 10.0 5.1 1i:o Hathorn No. 3 . . . . . . 8.3 6.6 9.5 Geyser. . . . . . . . . . . . . . . . 9 . 7 ... 1.7 3.9 3.4 8.8 12.2 Adams. . . . . . . . . . . . . . . . 1 1 . 0 5.1 11.7 Flat A-0. 2 . . . . . . . . . . . . . 10.5 5.0 ... 6.5 3.7 Pump well N-o. 4 . . , , , , , 1 2 . 0 67.8 23.1 6.3 2.1 Island. . . . . . . . . . . . . , . . 11.8 10.5 Crystal rock... . . . . . . . 1 o : o 84: 7 0.9 .. 88.0 New shonts well., . . . . . . 11.3
x
..
Although there is a fair agreement between t h e activities of t h e gases a n d waters, this agreement is not exact, nor is such t o be expected as t h e activity per liter of a n y gas Grill be largely influenced b y t h e r a t e of flow of t h e gas, which varies with t h e different springs a n d has not yet been measured. A similar s t a t e m e n t can be applied t o t h e results in Column j. The activity of t h e deposits per gram will depend not only 1
Jour. P h y s . Chem., 9 (1905). 320.
2
P r o c R o y . Soc., ( A ) 77 (1906). 472.
533
on t h e a m o u n t of radium precipitated from solution, b u t also upon t h e q u a n t i t y of other material precipit a t e d a t t h e same time. T h e fact t h a t t h e residues are radioactive shows t h a t t h e waters contain dissolved radium salts in addition t o dissolved emanation, b u t this fact is more precisely indicated b y t h e results under Column 4. T h e activity of t h e gases is not high, a result t o be expected owing t o t h e fact t h a t t h e flow of gas in t h e majority of t h e springs is quite large. T h e total activity of t h e maters is rather low, although t h a t of t h e Crystal Rock spring is considerably above t h e average. T h e activity of this spring, however, is not exceptional. A very large proportion of t h e activity due 'to dissolved radium salts, as shown in Column 4, is, however, quite exceptional a n d as this s t a t e m e n t applies t o all of t h e springs under Column 4 , with t h e exception of t h e Crystal Rock, i t is reasonable t o suppose t h a t i t probably also applies t o those not examined for dissolved radium salts. h l a n y of these springs contain considerable amounts of barium bicarbonate, as has been shown b y analyses made b y t h e S t a t e Department of Health of Kew York, H a t h o r n No. z carrying as much as 2 . 8 grains of barium bicarbonate per S. gallon. T h e Emperor spring has 0.14 grain of barium bicarbonate per U. S. gallon, t h e smallest amount of those tested. H a t h o r n K O . z carries t h e largest amount of radium in solution of those examined, b u t t h e Emperor does not carry t h e smallest amount. S o connection could be traced between t h e activities Bnd t h e quantities of t h e other salts in solution. Since these analyses were made, t h e hydrostatic level of t h e waters a t Saratoga Springs has distinctly changed, owing t o thecessation of theextensivepumping for commercial purposes which formerly took place. Accordingly, t h e flow of m a n y of t h e wells has increased. Whether this has also affected t h e radioactivity of t h e water cannot be predicted with certainty.
r.
BUREAUO F MINES,W A S H I X G T O N ~~
THE EFFECT OF FERRIC SALTS AND NITRITES ON THE ORTHO-TOLIDINE AND STARCH-IODIDE TESTS FOR FREE CHLORINE By J. W ELLMSA N D S . J. HAUSER
Received May 29, 1914
T h e authors in a previous paper' have suggested t h e use of a hydrochloric acid solution of ortho-tolidine in testing for very small quantities of free chlorine or hypochlorites in water, in place of a n acetic acid solution, which was first advocated b y Earl B. Phelps. T h e latter proposed t h e employment of ortho-tolidine as a quelitative test for free chlorine. T h e authors in t h e above-mentioned paper have modified t h e test as indicated a n d have further developed a colorimetric method for determining t h e q u a n t i t y of chlorine present in a water which had been treated with chlorine or with hypochlorites. T h e effect produced by t h e presence of nitrites or iron i n a water when using this method has been brought t o our attention, a n d has caused us t o make a few experiments, t h e results of which are tabulated below. 1
THISJOURNAL, 5, 915 and 1030.
T H E J O U R N A L OF I N D U S T R I A L A N D ENGINEERING C H E M I S T R Y
5 54
For comparative purposes we have made tests with t h e starch-iodide method also, a n d t h u s show t o what extent ferric salts a n d nitrites m a y interfere with t h e accuracy of both methods of determination. As it h a d been suggested t h a t a sulfuric acid solution of ortho-tolidine was less affected b y iron salts t h a n one of hydrochloric acid, comparative tests of t h e two acid solutions have also been made. Comparative tests have been made as well upon t h e delicacy of t h e tests for chlorine, when using a sulfuric acid solution of ortho-tolidine in place of a hydrochloric acid solution. TABLEI-EFFECT O F I
P. p. m. Fe
---
--
Ortho-tolidine in
HC1 sol.
-
Nine None None None None Faint trace Trace 0.01 0.02
Ndde None None None h-one None Trace 0.01 0.02
.
.
I
Hydrochloric acid sol. of ortho-tolidine C1 in . p. . p. m. added and indicated 0.01 0.02 0.03 0.04 0.05 0.06 0.07 0.09
---
Ortho-tolidine in
P. p. m.
.
None h'one None Trace Blue Deep blue Very deep blue Very deep blue Very deep blue
TABLE 11-RELATIVE DELICACY OF TOLIDINE A S COMPARED WITH
-
EFFECTOF IRONAS Fel(SOd3 r
StarchHzSOa iodide sol. test. .
0:05 0.07 0.09 0.10 0.20 0.50 0.70 1 .oo 2.00
t o substitute t h e former for t h e latter because i t is less affected b y ferric salts a n d nitrites. I n t h e authors' previous paper i t was quite clearly s t a t e d t h a t i t was believed t h a t t h e oxidation of t h e ortho-tolidine was t h e cause for t h e color changes observed. If this is t r u e all oxidizing agents will probably produce, under proper conditions, color changes in solutions of ortho-tolidine. I n proof of this t h e authors have made further experiments with a number of oxidizing agents a n d have found this t o be t h e case without exception, if t h e proper concen-
FERRIC CHLORIDE A N D FERRIC SULFATE. AND O F NITRITES O N ORTHO-TOLIDINE I N BOTH HYDROCHLORIC ACID A N D SULFURIC ACID SOLUTIONS, ALSO THEIREFFECTON THE STARCH-IODIDE TEST
I R O N AS
EFFECTOF IRONAS FeCL 7
Vol. 6 , KO.7
Fe 0.1 0.3 0.5 0.7
0.9 1.0 2.0 3.0 5.0
7.0
HzSOa sol. None None None None None
HC1 sol. Sone None None None Trace 0.01 0.03 0.04 0.09 Above 0.09
A SULFURIC ACID SOLUTION O F ORTHOA HYDROCHLORIC ACID SOLUTION
Sulfuric acid sol. of ortho-tolidine C1 in p. p. m. indicated None Trace 0.02 0.03 0.04 0.05 0.06 0.08
N. B.-Quantitative results expressed in terms of permanent chlorine standards, a s described in a previous paper for ortho-tolidine.
These results indicate, so far as t h e ortho-tolidine reagent is concerned, t h a t t h e presence of ferric iron or of nitrites in quantities t h a t are not infrequently found in water a n d sewage, might, if their presence was n o t suspected, give t h e impression t h a t chlorine or hypochlorites were present in t h e water. Interferences of this kind are common enough in practically every method of chemical analysis, b u t incorrect deductions m a y be easily guarded against b y careful qualitative tests. T h e presence of iron is easily ascertained, b u t as t h e table shows, t h e quantity which must be present t o produce a color is approximately 1.0 p a r t per million, or a n a m o u n t not usually found in surface waters, b u t which might be present in ground waters. High nitrites i n surface waters, unless badly polluted, are not likely t o be found, although sewage a n d especially sewage effluents m a y contain t h e m in amounts t h a t would interfere with t h e accuracy of t h e method. It will be noted t h a t t h e starch-iodide method is as much, if not more, affected b y t h e presence of nitrites andferric salts t h a n is t h e ortho-tolidine method. It apparently is t r u e from these tests t h a t a sulfuric acid solution of ortho-tolidine is not as much affected b y ferric salts a n d b y nitrites as is t h e hydrochloric acid solution. However, a sulfuric acid solution of ortho-tolidine is not as easily prepared as one of hydrochloric acid, a n d from t h e comparisons made i n Table 11, does not seem t o be able t o indicate quite as small amounts of chlorine as does t h e hydrochloric acid solution. It hardly seems worth while
0.03
EFFECT O F NITRITES
---
Ortho-tolidine in
Starchiodide test None None Trace
P. p. m. HzSOa N HC1 sol. sol. 0:Ol 0.03
0.05
Pale
0.07 0.09 0.10 0.30 0.50
..
Very deep blue
..
None None $one Trace 0.01 0.02 0.03 0.05
..
Gone None None None None None Trace 0.0 1
..
Starchiodide test Blue Deen blue Ver$ deep Very deep Very deep Very deep Very deep Very . deep .
....
blue blue blue blue blue blue
trations of t h e oxidizing compound a n d of acid were employed. T h e late D r . L. P. Kinnicutt' in quite a thorough investigation of t h e effect of oxidizing agents on ortho-tolidine showed t h a t ozone, nascent oxygen, sodium nitrite, ammonium persulfate, ferric chloride, ferric alum, potassium permanganate, potassium bichromate, sodium peroxide a n d lead peroxide gave color reactions with ortho-tolidine. T h e authors in their previous paper noted t h e color reactions produced b y bromine, iodine a n d nitrjc acid as well as b y potassium bichromate a n d potassium permanganate, which latter were mentioned b y Kinnic u t t . I n recent experiments t h e authors have found t h a t hydrogen peroxide, with which Kinnicutt was unable t o produce a color reaction w i t h ortho-tolidine, will also act similarly t o all t h e other oxidizing compounds, if t h e concentration of t h e acid in t h e solution is great enough. T h e probability of t h e presence of a n y of t h e oxidizing agents mentioned, excepting ferric salts a n d nitrites in natural waters, or even in sewage is rather remote. With proper precautions t h e ortho-tolidine method is applicable t o t h e usual conditions under which chlorine a n d hypochlorites are tested for in water. CIXCINNATI FILTRATION PLANT CINCINNATI, OHIO
A NEW METHOD FOR THE DETERMINATION OF HYDROCYANIC ACID AND THE ALKALI CYANIDES B y G.
E. F.
LUNDELLA N D J. A. BRIDGMAN
Received April 2 , 1914
One gravimetric a n d five different volumetric methods have already been proposed for $he above named determination. T h e authors' excuse for bringing o u t still another method is t h a t t h e proposed method is superior t o t h e older methods in several i m p o r t a n t respects. For t h e sake of comparison, t h e following
1
1 Data published as part of testimony taken in suit of Jersey City East Jersey Water Co.
US.
