THE INTERACTION BETWEEN XITRIC OXIDE AND HYDROGEN SULPHIDE I N THE PRESENCE O F WATER BY H. B. DUNNICLIFF, SARDAR MOHAMMAD AND JAI KISHEN
Recently, J. A. Pierce‘ has studied the reaction between nitric oxide and hydrogen sulphide from the thermodynamic point of view. He concludes that “the assumption of Thomson? that nitric oxide and hydrogen sulphide react to form ammonium sulphide and nitrous oxide is obviously incorrect: absence of the former by qualitative tests being sufficient indication of this. The counterclaim of Le Conte3 that the gases do not react a t all is likewise refuted.” He has established that the gases react together with formation of water, sulphur and nitrogen according to the stoichiometric equation : 2x0
+- 2H?S =
2H20
+ 2s + NP,
though the mechanism is more complex. The present work communicates a study of the reaction between the two gases in the presence of much water.
The Soluble Products of the Reaction between Nitric Oxide and Hydrogen Sulphide in the Presence of Water Hydrogen sulphide was prepared from ferrous sulphide and hydrochloric acid and purified by passing it first over dry iodine crystals and then through a dilute solution of sodium sulphide. X t r i c oxide was made by dripping a concentrated solution of sodium nitrite into an acidified solution of ferrous sulhate.^ Nitric oxide and hydrogen were passed into water in a two-litre flask frorn which air had been di,splaced by carbon dioxide gas. Milkiness due to sulphur was observed after some time. After a few hours the solution became yellow and more sulphur was formed and deposited. The interaction appeared to take place more rapidly when traces of nitrogen peroxide were previously introduced into the solution. The atmosphere over the solution remained clear throughout the reaction and the brown colour of nitrogen peroxide was never observed inside the flask. The yellow solution immediately became white when it was exposed to the air and some of the sulphur in the solution also seenied to coagulate. Cadmium carbonate was added to remove the excess of hydrogen sulphide and to deposit sulphur. The solution gave tests for ‘ammonium’ but hydroxylamine was absent. A nitrite was present but no nitrate. Acetic acid, when added to the solution obtained after the passage of the gases through m t e r for several hours, produced a transitory yellow colour which indicated the presence of some sulphur acid. Qualitative tests showed that a. thiosulphate was present but tetrathionate and other thionic acids were not detected. This contradicts the result previously an-
H. B. DUNNICLIFF, SARDAR MOHAMMAD AND J A I KISHEN
1722
nounced4 where it is stated that tetrathionate is present and nitrite is absent. The results given in the present article have been often confirmed.
Quantitative Determination of the Products of Reaction in Solution ‘Ammonium.’ Sodium hydroxide solution was added in excess to the original solution containing colloidal sulphur. Steam was blown through the solution and the ammonia absorbed in excess of standard sulphuric acid. Xitrite and thiosulphate were estimated by the following methods. Cadmium carbonate freshly precipitated from a solution of cadmium sulphate by ammonium carbonate was employed to remove the excess of hydrogen sulphide and to deposit sulphur from the solution. (a) Excess of potassium permanganate was added to oxidise completely I. both thiosulphate and nitrite. Ferrous sulphate was then added in excess and the excess of ferrous sulphate was back titrated against potassium ~ermanganate.~ (b). The thiosulphate was estimated by titration against a standard solution of iodine. Control experiments indicated that when the quantity of a nitrite in a mixture of a thiosulphate and a nitrite is not large, the thiosulphate could safely be determined by this method. The nitrite and thiosulphate were exactly oxidised as described above. 2). The nitrite formed as the result of oxidation was determined by the method of Bowman and Scott.6 The results of three experiments are recorded in Table I. The amount of ammonia was always in excess of that calculated for the nitrite and thiosulphate present, both when Merck’s extra pure cadmium carbonate or freshly precipitated and thoroughly washed cadmium carbonate was used. This was found to be due to small quantities of ammonia present in the cadmium carbonate. Hence, the solution which contained colloidal sulphur was used for determining ‘ammonium’ (V. S.). The quantities of the products formed in the reaction are small. Errors in estimation were reduced by taking large volumes of the solutions. I n the determinations of the nitrite the solution was evaporated to small bulk after oxidation. TABLE I The Quantitative Determination of the Products formed in Solution in the Reaction Composition of the solution in grams per (100X 1 0 ~ )C.C.
284
I21
150
152
-1.3
376
151
527
430
196 344
191 349
-1.4
2.6
NITRIC OXIDE, HYDROGEN SULPHIDE AND WATER
‘723
The Gaseous Products of the Reaction The apparatus for the estimation of nitrogen and nitrous oxide in the gaseous products of the reaction is described in “The Action of Hydrogen Sulphide on Solutions of Nitric Acid.”’ Nitric oxide obtained by the action of sodium nitrite on ferrous sulphate, was passed through a concentrated solution of caustic soda and then over solid caustic soda to purify it from traces
I . -
FIG.I (Diagrammatic)
of nitrogen peroxide. It was stored in the gas pipette, H1, (Fig. I ) over water the surface of which was covered with a layer of paroleine. The tower, D, connected with the reaction flask, C, contained cupric phosphate to remove the excess of hydrogen sulphide.* Paraffin wax had been run through the rubber tubing used as connections to prevent the action of nitric oxide on the rubber. Before commencing an experiment, the whole apparatus was swept
clean of other gases by a stream of carbon dioxide. The two gases were then admitted into the reaction flask, C, which would be easily shaken. The gases were allowed to stand for some hours and the reaction flask was occasionally shaken. When interaction appeared to be complete the gaseous mixture was swept forward through the cock F1,and a further supply of gases was introduced into C. Any excess of nitric oxide was absorbed in a series of vessels El, EP,(Fig. I ) EB,(Fig. 2 ) ’ of different forms each containing a mixture of
I724
El. B. DUNNICLIEF, SARDAR MOHAMhlAD AND JAI K I S H E N
five volumes of a saturated solution of potassium bichromate with one volume of concentrated sulphuric acid.g This mixture oxidises nitric oxide quantitatively to nitric acid and is stable a t ordinary temperatures. The residual gases were finally swept out by carbon dioxide and collected over caustic potash in the tube G, Fig. 2,’ through the cock F. The residual gases (S& and Sg) had then to be brought under combustion with excess of hydrogen in the pipette described in Fig. . . __ ,3.’ - The coctrsction produced should be equal to the volume of nitrous oxide. In Table I1 (i) and (ii) are given the results of two experiments performed under similar conditions, Le., the whole of the gases evolved were collected, the analyses being of average samples. In (ii),the gneeou? products froni the first two hours’ reaction were let out PLAT IN U M SPIRAL. through the air-vent rock Subsequent P L A T I UU M quantities of the two gases formed in the E X T f N5 I 0 N reaction were then collected in G.’ The G L A S S TUBE mixture hsd the same composition as the SET IN gas collected during the first two hours. BUNG This shows that the chemical change is RUBBER the same during those two periods of the BUNG reaction. In order to find out if the gases are ir, the same proportion in both the gas and PPfR ROO5 liquid phase the gases w-ere collected (:i) from t,he gaseous phase above the liquid and (b) by bubbling carbon dioxide through the liquid. It WRS found (vide results Table 111, i and i.a) that (a) contained a lower FIG.3 percentage of nitrous oxide than (h) Combustion Pipette (vide Table HI, ii). This may be due to the fact t,hat nitrous oxide, tile first reduction product, is removed from the sphere of action by its relatively high solubility in water or that nitrous oxide is formed in the liquid phase either exclusively or in greater quantity than in the gas phase. This point is under investigation. El1.
TABLE II Analysis of the Gaseous Products of the Reaction
i.
Vol. of the gas
Vol. of hydrogen
Vol. after combustion
Contraction N20
Pi?
C.C.
C.C.
C.C.
C.C.
C.C.
31 . o
42.8 61.6 71.9
.8 3.2 4.1
13.6 i. a 2 4 . 6 ii. 3 2 . 2
40.2
43.8
I
Composition 11 . 8
N2 E /C 20
21.4
13.2 13 .o
28.I
12.7
c’o
86.8 87 . o 87.3
NITRIC OXIDE, HYDROGEN SULPHIDE AND WATER
TABLE I11 The Gaseous Products formed when Hydrogen Sulphide and Xitric Oxide are bubbled through Water ContracN2 Percentage Vol. after Vol. of Vol. of
la
i.a i. ii.b
composition N2 0 N2
the gaa
Hydrogen
combuation tion
C.C.
C.C.
C.C.
C.C.
39.7 40.8 41.9
73.2 63.8 64.6
1.7
28.5
24.1 30'2
1.1
23 .o
7.5
22.7
30.2
5.6 4.6 24.8
94.4 95.4 75.2
The Effect of the Presence of Sulphuric Acid The reaction in the presence of sulphuric acid is more rapid a t first than when sulphuric acid is absent, but it slows down very quickly. The milkiness of the solution did not increase and only traces of ammonia were observed. The percentage composition of the residual gases is shown in Table IV.
TABLE IV The Gaseous Products (from gas and liquid phase) formed when Nitric Oxide and Hydrogen Sulphide are bubbled through Dilute Sulphuric Acid Vol. after Contrac- N2 N*0 xiz Vol. of Vol. of C.C. '7, % Hydrogen combustion tion the gas. C.C.
C.C.
With 5% H z S 0 4 i. 30.5 44.I With 10% HiSO4 ii. Ij.8 31.6
C.C.
C.C.
71.6
3.0
27.5
42.9
4.5
11.3
9.8
90.2
28.5
71.j
The results indicate the formation of a higher proportion of nitrous oxide when sulphuric acid is present. If the formation of nitrous oxide takes place mainly in the liquid phase, this may be due to the greater solubility of nitric oxide in sulphuric acid than in water. Since, after long passage of the gases ( S O and H2S) through water, the small amount of nitrite is the same as when the gases are passed for a short interval, it appears that either (a) the nitrite is a minor bye-product, or (b) that nitrite is formed as an intermediate product and systematically decomposed. The presence of sulphuric acid practically prevents the formation of ammonia in the solution. This suggests that such ammonia as is formed is nct produced in the gaseous phase (when on shaking it would be found in the suiphuric acid) hut in solution. This would confirm the observations of Pierce' who finds not only that nitrous oxide is not formed when dry nitric oxide and hydrogen sulphide are mixed, but that ammonia also is not a product of the reaction in the absence of water.
The Action of Nitric Oxide on Ammonium Nitrite and Dilute Solutions of Ammonia Products found in the Solution. Sitric oxide was passed into am(A) monium nitrite solutions of various concentrations in an atmosphere of hydrogen and the excess of nitric oxide was driven off by bubbling hydrogen through the solution. Nitrate was not detected by the most delicate tests. Titration
1726
H. B. DUNNICLIFF, SARDAR MOHAMMAD AND JAI KISHEN
against standard potassium permanganate showed that the amount of nitrite was unchanged. The solubility of nitric oxide in solutions of ammonium nitrite was also determined in the presence of hydrogen. The value found a t 20% agreed fairly with that given by Lunge for the solubility of nitric oxide in water. (Value determined = 0.0070 gram per roo c.c., Lunge found 0.0068 grams per I O O C.C.a t 2 0 % ) . There was no evidence that any chemical action takes place when nitric oxide is passed into dilute solutions of ammonia in an atmosphere of hydrogen.
The Action of Nitic Oxide on Solutions of Ammonium Sulphide The existence of a thiosulphate in the solution due to the interaction between nitric oxide and hydrogen sulphide suggests the formation of ammonium poly-sulphide (via ammonium sulphide and sulphur) as an intermediate product in the reaction. Hydrogen sulphide was passed into a solution of ammonia in the absence of air for some time and then excess of the gas was removed from the solution by bubbling hydrogen through it. A little more ammonium hydroxide was added to tend to produce ammonium sulphide from the hydrosulphide. When nitric oxide had been passed through the colourless solution for about 1 5 minutes, a yellow colour developed and sulphur was thrown down. This sulphur then gradually decreased in quantity as it dissolved in the solution, ultimately giving it an orange colour. The orange colour in the case of weak solutions (approximately N/zoo) was removed on passing nitric oxide for about twenty hours. Freshly prepared cadmium carbonate was added to deposit sulphur. The results showed that the polysulphides formed seemed to decompose into thiosulphate or thionic acids and sulphur. Since the amount of thiosulphate found in the solutions was small if cadmium carbonate was added immediately after the reaction, it appears that the thiosulphate is produced via the polysulphide. K h e n nitric oxide waa passed into N/33 ammonium sulphide for five hours, the thiosulphate formed was 0.2 gram per litre. The amount of thiosulphate increases considerably if the solution is allowed to stand. Only traces of nitrite were detected. When an insufficient amount of nitric oxide was kept in contact with a strong solution of ammonium sulphide over mercury for about 48 hours, the nitric oxide was completely absorbed in the solution which readily gave tests for a nitrite. There was no possibility of nitric oxide being in excess and forming nitrous acid via oxygen from the air, as i t was completely absorbed in the experiment. Traces of sulphate were present if nitric oxide was bubbled into very weak solutions for several hours when the polysulphide first formed seemed to decompose completely. This may have been due to decomposition of thiosulphate by hydrolysis (NHdpSzOa HzO = (NHdzS04 HzS (B). The Gaseous Products. The experiments could not be performed in the presence of carbon dioxide as the solution was completely decomposed when the apparatus was being washed with carbon dioxide. The percentage
+
+
NITRIC OXIDE, HYDROGEN SULPHIDE AND WATER
I727
of nitrous oxide and nitrogen determined from these experiments (NzO = 13.07~; NP = 87.07,) exactly corresponded with the percentage of these gases from the reaction between nitric oxide and hydrogen sulphide in the early stages (vide Table 11). This proved that the gaseous products are not obtained from ammonium sulphide and nitric oxide but probably from nitric oxide and hydrogen sulphide in the gas phase, the hydrogen sulphide being drawn out of the hydrolysed ammonium sulphide solution by carbon dioxide. To overcome the difficulty of providing an inert atmosphere over the solution, another apparatus (Fig. 4) was connected with the apparatus for the gas analysis (Fig. 2). The air from the capillary tube was completely expelled by using the same nitrometer as a pump. Nitric oxide prepared in A, by
FIG.4
Thiels’s method3 was admitted into the nitrometer, N. A known volume of a solution of ammonium sulphide was drawn into the nitrometer from the cup, G. The nitrometer was shaken occasionally and, after the desired interval for reaction, the residual gases were driven into the apparatus for gas analysis (Fig. 2 ) by raising the reservoir of the nitrometer and using a current of carbon dioxide. A mixture of 50 c.cs. of N/33 ammonium sulphide solution with I O C.C. of ammonium hydroxide of the same strength was exposed to 80 C.C. of nitric oxide. After 19 hours the contraction was 26 C.C. The gas collected over caustic potash was 1 1 to 1 2 c.c., the balance (nitric oxide) having been absorbed in the dichromate mixture. The results of two experiments performed under similar conditions are shown in Table V.
TABLE V Analysis of the Gaseous Products of the Reaction between Xitric Oxide and Ammonium Sulphide Vol. of Vol. of Vol. after ContracN2 Composition the gas C.C.
i. ii.
11.4 12.0
Hydrogen
N2 0
combustion tion
C.C.
C.C.
C.C.
18.6 21.6
26.8 30.2
3.4
3.2
8.2 8.6
% 28.I 28.4
5 9 /O
71.9 71.6
Nitric oxide was in excess in these experiments. Experiments were performed in which the excess of the reducing agent Le., ammonium sulphide, was exposed to nitric oxide. In Table VI are given
1728
K. B. DUNNICLIFF, SARDAR MOHAMYAD AYD J.41 KISHEN
the results of two experiments carried out under similar conditions in which 82 C.C. of nitric oxide, were allowed to react with j o C.C.of ammonium sulphide solution (approximately N/Io) and I O C.C.of 9 / 3 3 ammonium hydroxide. After 19 hours the residual gas, which was free from nitric oxide, was about 2 1 C.C. in the first experiment and 1 7 . 2 C.C.in the second experiment.
TABLE VI Analysis of Residual Gas from the Action of Sitric Oxide with Excess of Ammonium Sulphide
i. ii.
Vol. of the gas
Vol. of Hydrogen
Vol. after Contraccombustion tion
c
C.C.
C.C.
C.C.
C.C.
21.2
17.2
33.4 31 . o
54.5 48.2
C.C.
S,
x2
ru'2 0
sc
R
0.1
21.1
0.0
IO0 . o
0.0
17.2
0.0
100.0
These experiments show that when an excess of the reducing agent is used, the gaseous product of the reaction consists of pure nitrogen. The percentage of nitrous oxide is increased by using an excess of the oxidising agent,, i.e. nitric oxide. Bancroftla from a study of the reduction of nitric acid by metals arrived at the same conclusions: "In the first case there is never an appreciable concentration of the reducing agent, hence its potential is low, and the reduction will not go sa far. In the second case there is always an excess of reducing agent and the reduction should go to a lower stage than in the first case. There is a little chance for nitric acid to react with the intermediate products. An excess of reducing agent will cause more complete reduction to a lower stage." It also shows that nitric oxide is reduced to nitrogen via nitrous oxide under favourable conditions and is conclusive evidence that nitrous oxide is reduced to nitrogen by hydrogen sulphide (or ammonium sulphide). The Action of Nitric Oxide on Ammonium Thiosulphate The Products of the Reaction in Solution. On passing nitric oxide (A). into solutions of ammonium thiosulphate in an atmosphere of hydrogen, a transitory yellow colour is observed with deposition of sulphur in small quantities. The decomposition of the thiosulphate increases with the decrease in the concentration of the solutions but the amount of ammonia in a solution remains constant. Table VI1 shows the decomposition of solutions of ammonium thiosulphate of different strengths.
TABLE 1-11 The Decomposition of Ammonium Thiosulphate by Xitric Oxide Composition of the solution grams per IOO C.C.
1.
ii.a. b. iii.
Strength of the solutions
(S2O3Ib taken
S /6 X,/19.7 X/19.7 S , ' 7 7 . 14
I ,867 0.568 0.568
0.145
I,S~G~)''
left I
.8j8
0 . j40
0.529 0.119
Decomposition Percentage decomposition
0.009 0.028 0.039 0.026
0.;
4.9 6.9 17.9
I729
NITRIC OXIDE, HYDROGEN SULPHIDE AND WATER W
uLo =
N cl
N 3
Lo
9
9
9
;
0
0
I
x
9
.-3 B
3
e 0
cc 0
cc 0
0
I .
-
h rn
I .
"i
9
i
0
0
"
.-
-
I
i
"i
w
"i e
0 0
ic 10 d 0
rn
10
i
d
=
h
h
h
z
4
h
2 . -
I -
.-
.e
,-
H. B. DUNNICLIFF, S.4RD4R MOHAXXAD A S D JAI KISHES
I730
Sulphate was found to be present in small quantities but tetrathionate was not detected. Sitric oxide was passed into N j z o ammonium thiosulphate solutions for different intervals but the nitrite formed was negligible in all the stages of the reaction. If formed, nitrite is probably decomposed in all stages of the reaction by comparatively strong solutions of ammonium thiosulphate (vide foot-note to Table VI11 p. 1729). The transitory yellow colour observed throughout the reaction may be the result of interaction between the nitrite formed and the thiosulphate present.“ However, an increase in the amount of nitrite was observed (Table T’III) in the early stages of the reaction when nitric oxide was passed into mixtures of equal volumes of ammonium thiosulphate and ammonium nitrite solutions. In the later stages of the reaction, decomposition of nitrite is noticed When nitric oxide was passed into about K/zo ammonium thiosulphate solutions, sulphate was formed. The results shown in Table IX give the amount of change effected in different intervals of time and it will be observed that there is no regular relationship between the thiosulphate decomposed and the sulphate formed. A small but continuous decrease in the amount of ammonia was observed. The solution was alkaline to litmus after the passage of the gas for nine hours. TABLE IS The Amount of Sulphate formed when Nitric Oxide is passed into Ammonium Thiosulphate for different intervals Quantities are shown in grams per litre. I 2 3 4
Time of Passage of Gas (Hours). 1.j 2.5 4.j 9.0 Thiosulphate taken as (S20a)” 5.654 5.654 5.654 5.654 Thiosulphate left as ( S 2 0 J ” 5.j99 5.462 5.101 4.604 Thiosulphate decomposed as (S20a)” o.ojj 0.192 0.55.3 1.050 Sulphate formed as (SOi)” 0 . 0 4 5 0.094 0.297 0.328 (iVHa)’Corresponding to (SO,)” formed 0.017 0.035 0 . 1 1 1 0 . 1 2 3 (KH,)’ corresponding to (S203)” left I , 799 I . 7 j6 I . 639 I . 480 Total of (v) and (vi) 1.816 1.791 1.750 1.602 (KHJ’ corresponding to (S20,)”taken 1.818 1.818 1.818 1.818 Percentage. Decrease in ( S H I ) ’ -1.j -3.7 - 1 1 . 8 B. The Gaseous Products of f h e Reaction. About 2 jo C.C. of nitric oxide were kept in contact with 2 5 0 C.C.of ammonium thiosulphate solution (about Kt’50) for twenty hours. The volume of the residual gases collected over caustic potash was small. The results of two experiments are shown in Table X. i. ii. iii. iv. v. vi. vii. viii. is. x.
TABLE S Analysis of the Gaseous Products of the Reaction between Sitric Oxide and Ammonium Thiosulphate
i. ii.
Vol. of the gas.
Vol. of Hydrogen.
Vol. after Contraccombustion tion
c.c.
c.c.
C.C.
12.5
24.I
35.9
0.j
I O .6
IS.?
28.2
0.6
S:
Composition
N20
S:
11.8
5.6
94.4
10.0
5.i
94.3
173’
KITRIC OXIDE, HYDROGEN SULPHIDE AXD WATER
The Action of Nitric Oxide on Solutions of Ammonium Tetrathionate Ammonium tetrathionate was prepared and was estimated by the method of A. Kurtenacker.12 On passing nitric oxide into solutions of ammonium tetrathionate of various concentrations, a slight turbidity but no coloration was noticeable. The solution became acidic. (Solutions of ammonium tetrathionate become acidic also on long standing). As in the thiosulphate experiments, the total concentration of ammonia in the solution remained unchanged. The solutions did not give tests for a nitrite when the gas was passed for four hours.
TABLE XI The Decomposition of Ammonium Tetrathionate Solution by Nitric Oxide Composition of the solution: gram/Ioo C.C. Strength of the solution
i. ii. iii. iv.
Time in (S,O,)” hours for taken passing KO
(S,O,)”
left
(S,OS)” Percentage decomposed decomposition
K/29.92
I .o 2 .O
0.869 0.869
0.869 0.849
0.000
-Y/~g.gz B’/20.j1
4.0
I
,091
0.700
0,391
2.3 35.9
N/32.91
4.0
0.680
0.196
0.484
71.2
0.020
0.0
Kitric oxide was also passed into mixtures of ammonium nitrite and ammonium tetrathionate solutions. The results were comparable with those obtained from mixtures of ammonium thiosulphate and ammonium nitrite solutions. (vide Table X I ) .
TABLE XI1 Shows the Formation and Decomposition of Nitrite when Nitric Oxide is passed into Mixtures of Ammonium Tetrathionate and Ammonium Nitrite Solutions Composition of the solution: grams per IOO C.C. Strength of solutions
21.94
ii.
B’ (Sa06)” -
Time in hours for KO
(NO,)’
1.54
0.Io;
0.127
fo.
4.0
0.10;
0.071
-0.034
taken
(NO?)’after the reaction*
Increase or Decrease
022
I
I
21.27
21.94 *vide footnote to Table VIII, page
1729.
I732
H. B. DCNSICLIFF, SARDAR MOHAMMAD AND JAI KISHEN
In solution tetrathionates like thiosulphates are not affected by a nitrite in a neutral medium. In the presence of an acid, the solution of a tetrathionate became yellow. For this reason the amount of tetrathionate was not determined in the above experiments as all the methods recommended for the estimation of tetrathionates involve the use of an acid. The production of a transitory yellow colour is not peculiar to thiosulphates in the presence of an acid and a nitrite as stated by Falcoila.ll The Action of Hydrogen Sulphide on Nitrous Oxide It appears from the results given in Tables 11, I11 and IV that nitric oxide ran be reduced through nitrous oxide to nitrogen. To confirm this pure nitrous oxide was collected over hydrogen sulphide solutions in the nitrorneter N (Fig. 4) in the presence of water. An analysis of the residual gases after 30 hours is given in Table XIII. Quantitative reduction of nitrous oxide to nitrogen was recorded in both experiments. T.4BLE XI11 An Analysis of the Gas which results when Sitrous Oxide reacts with Hydrogen Sulphide Solutions
Volu. of the gas
To:. of
C.C.
r.c.
C.C.
C.C.
I.
20.4
j2.6
20.4
100
11.
20.0
32.4 32.0
q2.2
20.4
IO0
H?
Vol. after combustion
S?
N* ( '
T h e liquid phase containeti sulphLr and readily gave tests for ammonia, T!iis reaction is under further investigation. The Action of Hydrogen Sulphide on Solutions of Ammonium Nitrite Bagster13 observed that hydrogen sulphide acts slowly upon ammonium nitrite converting it into ammonia. Small quantities of nitrogen are also evolved when solutions of ammonium nitrite are kept in contact with hydrogen sulphide for a number of days. The residual gases consisted of nitrogen only. Summary and Discussion Sitric oxide reacts with hydrogen sulphide solution giving ammonium thiosulphate, ammonium nitrite, sulphur, nitrous oxide and nitrogen. Animonium sulphide solution is decomposed by nitric oxide forming 2). polysulphides of ammonium and small amounts of ammonium thiosulphate and nitrous oxide and nitrogen are evolved. Excess of the reducing agent gives pure nitrogen but excess of the oxidising agent increases the yield of nitrous oxide. 3). Saturated hydrogen sulphide solution completely reduces nitrous oxide to nitrogen and ammonia. 4). ru'itric oxide slowly converts dilute solutions of ammonium thiosulphate into ammonium sulphate. Small quantities of nitrogen are formed. I).
NITRIC OXIDE, HYDROGEN SULPHIDE AND WATER
I733
j). Bagster observed that hydrogen sulphide slowly converts ammonium nitrite into ammonia. It has been shown that small amounts of nitrogen are also evolved. Pierce stated that dry hydrogen sulphide and dry nitric oxide react giving nitrogen and not nitrous oxide. The formation of nitrous oxide is probably due to the water present. Zimmermann14 observed that aqueous solutions of nitric oxide have a greater conductivity than pure water. He considered that the solution is in part a chemical process giving ionisable substances one of which is possibly Angeli’s acid H2NZ03 (i. e., HzO zIiO), derivatives of which are known and which, upon acidification, give nitric oxide. This Angeli’s acid may be supposed to react upon hydrogen sulphide.‘
+
HzS
+ O
