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A convenient method for the generation of hydrogen sulphide gas
A
CONVENIENT METHOD FOR THE GENERATION OF HYDROGEN SULPHIDE GAS.* BY ABRAHAM H E N W O O D , Sc.D., RAYMOND M. GAREY, B.S., W O O L F GOLDBERG, B.S., and ELMER FIELD, M.S.
CentralHighSchool,Philadelphia. THE method that we wish to recommend to the attention of chemists has the following characteristics: (a) The apparatus required is very simple and inexpensive, consisting merely of a I5-cm. test-tube fitted with singly bored cork and delivery tube. (b) The volume of H2S per unit volume of charge is exceedingly high. Ten c.c. of the charge yields about 20oo c.c. of H2S gas. (c) The gas is evolved in a copious stream upon the application of a bunsen burner flame not more than I inch high. This evolution continues at an undiminished rate till the charge is exhausted. (d) The evolution of gas ceases within one minute after the flame is removed. This is a decided merit as it minimizes the danger of contaminating the air of the laboratory. (e) After exhaustion of the charge, the residue, which consists of a dry friable mass, is readily removed from the tube, leaving it ready for a new charge. ( f ) This residue is small in bulk and its disposal is free from all the inconveniences attending the disposal of the gritty residue and " spent acid " of the conventional iron sulphide-acid method. (9) The H=S is pure, free from hydrogen and spray of metallic salt solutions. These points facilitate absorption and render a wash bottle unnecessary. The reaction utilized is that of sulphur on paraffin wax 1 at a temperature somewhat above that at which sulphur is in the plastic state. As stated above, the flame of a bunsen burner adjusted to a height of about I inch sets up the condition required for a copious evolution of the gas. * Communicated by Doctor Henwood. 1j. S. GALLE'rLE'¢:Chem. N e w s , 24, 162 (I87I). 685
686
HENWOOD, GAREY, GOLDBERG, FIELD.
[J.F.I.
The action seems to be substantially as follows: CnH2n+2+(n+I)S
• (n+I)H2S+nC
We have found it convenient to incorporate the reacting materials with finely divided ignited asbestos. This facilitates the removal of the spent charge and seems to minimize the danger of volatilizing paraffin andsulphur. The apparatus is arranged as sketched in Fig. I. FIG. I,
I
m
x=c .
As the action proceeds the flame is shifted to positions progressively nearer the open end of the tube. A charge of 5 grams, or about 5 c.c., gives sufficient H2S to precipitate 3 grams of copper as CuS. This method has been tried out with a class of about forty students in qualitative analysis with entirely satisfactory results. We feel that the method will be we!corned in colleges and analytical laboratories. On the Impact with Liquid Surfaces of Solid Bodies of Various Shapes. G. ERIC BELL. (Phil. Mag., Feb., I925.)--A series of interesting shadow photographs is given, showing cvlinders with axes vertical entering water or turpentine with a velocity of about 25o cm. per sec. With water but little disturbance of the surface takes place, provided the cylinder is clean. If it is coated with oil, a basin-like cavity forms at the surface. A cylinder pointed at the lower end enters the liquid smoothly. In turpentine the disturbance produced is more marked than in water. G.F.S.
CONVENIENT METHOD FOR THE GENERATION OF HYDROGEN SULPHIDE GAS.* BY ABRAHAM H E N W O O D , Sc.D., RAYMOND M. GAREY, B.S., W O O L F GOLDBERG, B.S., and ELMER FIELD, M.S.
CentralHighSchool,Philadelphia. THE method that we wish to recommend to the attention of chemists has the following characteristics: (a) The apparatus required is very simple and inexpensive, consisting merely of a I5-cm. test-tube fitted with singly bored cork and delivery tube. (b) The volume of H2S per unit volume of charge is exceedingly high. Ten c.c. of the charge yields about 20oo c.c. of H2S gas. (c) The gas is evolved in a copious stream upon the application of a bunsen burner flame not more than I inch high. This evolution continues at an undiminished rate till the charge is exhausted. (d) The evolution of gas ceases within one minute after the flame is removed. This is a decided merit as it minimizes the danger of contaminating the air of the laboratory. (e) After exhaustion of the charge, the residue, which consists of a dry friable mass, is readily removed from the tube, leaving it ready for a new charge. ( f ) This residue is small in bulk and its disposal is free from all the inconveniences attending the disposal of the gritty residue and " spent acid " of the conventional iron sulphide-acid method. (9) The H=S is pure, free from hydrogen and spray of metallic salt solutions. These points facilitate absorption and render a wash bottle unnecessary. The reaction utilized is that of sulphur on paraffin wax 1 at a temperature somewhat above that at which sulphur is in the plastic state. As stated above, the flame of a bunsen burner adjusted to a height of about I inch sets up the condition required for a copious evolution of the gas. * Communicated by Doctor Henwood. 1j. S. GALLE'rLE'¢:Chem. N e w s , 24, 162 (I87I). 685
686
HENWOOD, GAREY, GOLDBERG, FIELD.
[J.F.I.
The action seems to be substantially as follows: CnH2n+2+(n+I)S
• (n+I)H2S+nC
We have found it convenient to incorporate the reacting materials with finely divided ignited asbestos. This facilitates the removal of the spent charge and seems to minimize the danger of volatilizing paraffin andsulphur. The apparatus is arranged as sketched in Fig. I. FIG. I,
I
m
x=c .
As the action proceeds the flame is shifted to positions progressively nearer the open end of the tube. A charge of 5 grams, or about 5 c.c., gives sufficient H2S to precipitate 3 grams of copper as CuS. This method has been tried out with a class of about forty students in qualitative analysis with entirely satisfactory results. We feel that the method will be we!corned in colleges and analytical laboratories. On the Impact with Liquid Surfaces of Solid Bodies of Various Shapes. G. ERIC BELL. (Phil. Mag., Feb., I925.)--A series of interesting shadow photographs is given, showing cvlinders with axes vertical entering water or turpentine with a velocity of about 25o cm. per sec. With water but little disturbance of the surface takes place, provided the cylinder is clean. If it is coated with oil, a basin-like cavity forms at the surface. A cylinder pointed at the lower end enters the liquid smoothly. In turpentine the disturbance produced is more marked than in water. G.F.S.