- Email: [email protected]
The electrolytic determination of mercury
April, 189x.]
L‘hw~icczl
.%cfic)x.
297
The deposition of metal occurred at the ordinary temperaturc. At the beginning of the decomposition the liquid showed a beautiful deep purple color, but as the metal separated, it rapidly became lighter and finally colorless, Vpon inclining the tlish in which the precipitation was made, thus exposing a fresh metal surface, the latter The precipitation of metal was remained perfectly clear. complctcd. (3) The conditions here were nearly the same as in the The total dilution of liquid equalled 200 preceding trial. cc. while the current. gave 16 cc. of OH gas per minute. The metallic rhodium was precipitated upon copper-plated platinum dishes. It xvas rather black in color, very compact It was washed without any diffiand perfectly adherent. culty. Hot water was used for this purpose. The drying was done upon a warm iron plate. The results ohtainecl accord so well with the theory that the accuracy of the method cannot be questioned. The rapidity with which the metal is deposited, and the ease with which it may be handled also recommend this method of estimation. CHEYICAL I_~B~R,~TO~~Y OF TIIE UNIV. OF PA., PHILAIHXPIIIA,
TW
February
13, 1831.
ELEC’l’ROI~YTIC IJETERMINATION MERCURY.
OF
l3u EDGAI~ 1:. SMITH. [Read at the sinfed
nzeljting, held February
17, ~891.1
In gravimetric analysis mercury is frequently obtained as sulphide. To weigh it as such, or to convert it into some form suitable for weighing, requires much time and close attention to insure results that will be at all satisfactory. It is, therefore, better to have recourse to the electrolytic method of determination. As mercury sulphide dissolves quite readily in the fixed alkaline sulphides, I electrolyzed such solutions. The results show that this
Chwticnl
298
Seclim.
[J. F. I.,
procedure affords a very accurate and clean method .estimation of this metal. The sodium sulphide was prepared as described paper relating to the determination of gold. Its gravity was 1.19. Solutions of mercuric chloride, containing a amount of metal, were first tried. The table shows ditions of cxpcrimcnt and the results : xercury
present grams
in
Sodium sulphide present. sp. gr. I”$
Total dilution.
Current in cc. OH gas per minute.
for the in the specific known the con_
1 Mercuryfound.
The precipitation extended through the night. The deposited mercury was gray in color and very compact. Qnly once was a tendency to the fluid form observed. Hot water was used for washing, Th.e metal was dried by holding the platinum dish in the palm of the hand and blowing gently upon the deposit. If mercury and arsenic are both present in a solution of sodium sulphide, the current will throw out the former. It will not carry down any arsenic. This is evident from the ,two analyses that follow: Mercury present.
Arsenic present.
Sodium sulphide.
Total
dilution.
Current in cc. OH gas per minute.
mercury found.
In the communication upon the deposition of gold from sodium sulphide solutions, mention is made that gold and tin could not be separated electrolytically when present together in a solution of that kind, .I was, therefore, rather surprised to discover that mercury could be separated from
April,
Chmicnl
1891-l
Secdim.
299
The conditions of experisuch circumstances. lnent were similar to the following: The solution contained 01903 gram of mercury, 0*12oo The total dilugram of tin, and 30 CC. of S~&UI~ sulphide. tion was I25 CC. The current gave 2 cc. of OH gas per lnillute, and acted for twelve hours, The precipitated mercury weighed O* Igog gram. The filtrates from the mercury deposits did not show even traces of this metal when they were examined. tin under’
&?.fIICAL LABORATORY 0F nfE PHILADELPHIA,
TIE ELECTROLYTIC
[Red
Uslv. 0~ PA., February
13, 1891.
DETERMINATION
OF
GOLD.
af the stafed meefiny, held February 17, 1891.]
Gold has been estimated electrolytically in solutions, containing it as a double cyanide, or in the presence of sodium phosphate and phosphoric acid. From recent experiments I am satisfied it can be determined in the same manner by the decomposition of solutions of sodium sulphaurate. Years ago I’arodi and Mascazzini (2’kt.J Amdyt. Che~ifl, 18,588), showed that antimony was completely precipitated fromsolutions of its ammonium sulpho-salt by the electric current. Classen elaborated this idea (Ber. 14, 1622; 17, WQ; 1’7, 2245; 18, I I IO),substituting sodium sulphide for ammonium sulphidc, and succeeded in effecting a most excellent separation of antimony from both tin and arsenic. The sodium sulphide, used in the experiments recorded in this communication, was prepared by supersaturating a definitevolume of caustic soda (1.3 sp. gr.) with hydrogen sulphidegas. An equal amount of caustic soda was then added,and the current of hydrogen sulphide continued for * ‘Ome hours through the solution. The liquid was then raPidly Concentrated until a crystalline scum appeared uPonits surface. In ‘this condition it was placed in bottles
L‘hw~icczl
.%cfic)x.
297
The deposition of metal occurred at the ordinary temperaturc. At the beginning of the decomposition the liquid showed a beautiful deep purple color, but as the metal separated, it rapidly became lighter and finally colorless, Vpon inclining the tlish in which the precipitation was made, thus exposing a fresh metal surface, the latter The precipitation of metal was remained perfectly clear. complctcd. (3) The conditions here were nearly the same as in the The total dilution of liquid equalled 200 preceding trial. cc. while the current. gave 16 cc. of OH gas per minute. The metallic rhodium was precipitated upon copper-plated platinum dishes. It xvas rather black in color, very compact It was washed without any diffiand perfectly adherent. culty. Hot water was used for this purpose. The drying was done upon a warm iron plate. The results ohtainecl accord so well with the theory that the accuracy of the method cannot be questioned. The rapidity with which the metal is deposited, and the ease with which it may be handled also recommend this method of estimation. CHEYICAL I_~B~R,~TO~~Y OF TIIE UNIV. OF PA., PHILAIHXPIIIA,
TW
February
13, 1831.
ELEC’l’ROI~YTIC IJETERMINATION MERCURY.
OF
l3u EDGAI~ 1:. SMITH. [Read at the sinfed
nzeljting, held February
17, ~891.1
In gravimetric analysis mercury is frequently obtained as sulphide. To weigh it as such, or to convert it into some form suitable for weighing, requires much time and close attention to insure results that will be at all satisfactory. It is, therefore, better to have recourse to the electrolytic method of determination. As mercury sulphide dissolves quite readily in the fixed alkaline sulphides, I electrolyzed such solutions. The results show that this
Chwticnl
298
Seclim.
[J. F. I.,
procedure affords a very accurate and clean method .estimation of this metal. The sodium sulphide was prepared as described paper relating to the determination of gold. Its gravity was 1.19. Solutions of mercuric chloride, containing a amount of metal, were first tried. The table shows ditions of cxpcrimcnt and the results : xercury
present grams
in
Sodium sulphide present. sp. gr. I”$
Total dilution.
Current in cc. OH gas per minute.
for the in the specific known the con_
1 Mercuryfound.
The precipitation extended through the night. The deposited mercury was gray in color and very compact. Qnly once was a tendency to the fluid form observed. Hot water was used for washing, Th.e metal was dried by holding the platinum dish in the palm of the hand and blowing gently upon the deposit. If mercury and arsenic are both present in a solution of sodium sulphide, the current will throw out the former. It will not carry down any arsenic. This is evident from the ,two analyses that follow: Mercury present.
Arsenic present.
Sodium sulphide.
Total
dilution.
Current in cc. OH gas per minute.
mercury found.
In the communication upon the deposition of gold from sodium sulphide solutions, mention is made that gold and tin could not be separated electrolytically when present together in a solution of that kind, .I was, therefore, rather surprised to discover that mercury could be separated from
April,
Chmicnl
1891-l
Secdim.
299
The conditions of experisuch circumstances. lnent were similar to the following: The solution contained 01903 gram of mercury, 0*12oo The total dilugram of tin, and 30 CC. of S~&UI~ sulphide. tion was I25 CC. The current gave 2 cc. of OH gas per lnillute, and acted for twelve hours, The precipitated mercury weighed O* Igog gram. The filtrates from the mercury deposits did not show even traces of this metal when they were examined. tin under’
&?.fIICAL LABORATORY 0F nfE PHILADELPHIA,
TIE ELECTROLYTIC
[Red
Uslv. 0~ PA., February
13, 1891.
DETERMINATION
OF
GOLD.
af the stafed meefiny, held February 17, 1891.]
Gold has been estimated electrolytically in solutions, containing it as a double cyanide, or in the presence of sodium phosphate and phosphoric acid. From recent experiments I am satisfied it can be determined in the same manner by the decomposition of solutions of sodium sulphaurate. Years ago I’arodi and Mascazzini (2’kt.J Amdyt. Che~ifl, 18,588), showed that antimony was completely precipitated fromsolutions of its ammonium sulpho-salt by the electric current. Classen elaborated this idea (Ber. 14, 1622; 17, WQ; 1’7, 2245; 18, I I IO),substituting sodium sulphide for ammonium sulphidc, and succeeded in effecting a most excellent separation of antimony from both tin and arsenic. The sodium sulphide, used in the experiments recorded in this communication, was prepared by supersaturating a definitevolume of caustic soda (1.3 sp. gr.) with hydrogen sulphidegas. An equal amount of caustic soda was then added,and the current of hydrogen sulphide continued for * ‘Ome hours through the solution. The liquid was then raPidly Concentrated until a crystalline scum appeared uPonits surface. In ‘this condition it was placed in bottles