The excess of lead is then removed by passing hydrogen sulphid gas through the fluid or by shaking well with 4 gm.
Hydrogen sulphid is easily prepared in the simple apparatus shown in Fig.
A small quantity of iron sulphid is placed in the test-tube; a little dilute hydrochloric acid is added; the cork is replaced; and the delivery tube is inserted to the bottom of fluid to be tested.
It is allowed to cool, and hydrogen sulphid gas is passed through it for about five minutes.
The presence of sulphid in appreciable amounts was demonstrated showing that the sulphur is present, at least in part, in the form of sulphid and not as sulphonate as is claimed.
Arsenic is present in such small amounts that the ordinary hydrogen sulphid test failed to show its presence and the delicate Gutzeit’s test had to be used to detect it.
If this seems to be losing its effect after a week, change for mercurial ointment or a solution of sulphid of potassium, or of hyposulphite of soda, 3 drams to the quart of water.
The precipitate was treated in the usual manner of the group separation with warm ammonium sulphid solution.
The bismuth sulphid obtained is dissolved in nitric acid and from the solution obtained the bismuth is precipitated by addition of an excess of ammonium hydroxid and ammonium carbonate.
The ammonium acetate extractions from each specimen were combined and treated with hydrogen sulphid, the precipitated lead sulphid filtered off and washed, and ignited with sulphuric acid at a low heat.
The results by the sulphid method are somewhat lower than those by the Kollo method, but duplicates agree fairly well.
It is seen from the tabulation that the results obtained by the Kollo method (Method C) are higher than those by the sulphid method (Method D) and that duplicate determinations show a rather wide variation.
Barium Sulphid 2 drams Zinc oxid 3 drams Starch 3 drams Permanganates and sulphids mutually destroy each other, and therefore the addition of the small amount of potassium permanganate cannot serve any useful purpose.
The above list will hopefully give you a few useful examples demonstrating the appropriate usage of "sulphid" in a variety of sentences. We hope that you will now be able to make sentences using this word.
