Aug. 18, 1923 
Sulphur Compounds in Dry Lime-Sulphur 
3 2 7 
Any sulphur adhering to the two pieces of glass tubing which dipped 
into the solution contained in flask A, is added to the bulk of sulphur in 
the crucible, and the contents of the crucible are treated with 1 to 10 
hydrochloric acid to dissolve the precipitated calcium carbonate. The 
residue is well washed, after which the crucible and contents are dried 
at ioo° C. for one hour, weighed, ignited, and again weighed. The 
difference in weight represents the sulphur present in the polysulphid 
form together with any free sulphur. 
The sulphur evolved as hydrogen sulphid, and contained in the solu¬ 
tion in flasks No. 1 and No. 2 4 as sodium sulphate, is transferred to 500 
cc. graduated flasks and heated upon the steam bath with the flasks 
stoppered until complete oxidation is assured. The solution is cooled 
and a few drops of methyl orange are added, followed by hydrochloric 
acid until the solution is slightly acid. It is then boiled to destroy the 
hydrogen peroxid and to drive out all carbon dioxid, cooled, and made 
to volume. 
To 50 cc. portions of the solution % cc. of 1 to 1 HC 1 is added, and the 
sulphate determination is carried out in the usual manner. 
method b 
In this method the solutions used are: Hydrated sodium peroxid; 
approximate N/2 HC 1 ; barium chlorid solution 1 to 10; N/20 iodin; and 
starch. 
procedure 
Five-tenths gm. dry lime-sulphur is placed in a small Erlenmeyer 
flask, 50 to 60 cc. of recently boiled and cooled distilled water added, 
and the solution titrated, with vigorous agitation of the contents of the 
flask, with approximate N/2 HC 1 , and 3 to 4 drops of methyl orange 
indicator introduced just previous to the end-point of the reaction. The 
addition of HC 1 is continued until the pink color developed persists in the 
solution after the flask has stood for two or three minutes. The 
amount of HC 1 used determines the total basicity of the solution. 
The prepared Na 3 0 2 solution is then added to flasks No. 1 and No. 2 
as in Method A. 
Another 0.5 gm. sample of the dry lime-sulphur mixture is transferred 
to the reaction flask, A, and oxygen-free N passed through the apparatus. 
To the separatory funnel is added the same quantity of approximate 
N/2 HC 1 which was required to neutralize the basic constituents con¬ 
tained in 0.5 gm. of dry lime-sulphur. The sides of the funnel are 
rinsed with 50 cc. of distilled water and the diluted acid solution is care¬ 
fully admitted to the reaction flask without interruption of the slow 
passage of N. The funnel is again rinsed with a small amount of water, 
a few drops of methyl orange added, and the solution run carefully into 
the reaction flask. 
The solution contained in flask A should develop a pink color provided 
all the acid has been removed from the separatory funnel and the separ¬ 
ated sulphur has not completely absorbed the indicator. 
The passage of N through the apparatus is continued until all traces 
of H 2 S have been expelled from flask A. From this point the procedure 
is similar to that given under Method A. 
4 Flask No. a is used as a precaution and will be found to contain no sulphur, provided the gas is not 
forced through the apparatus at too rapid a rate. 
