Synthetic Inorganic Chemistry
SULPHUR 173
SULPHUR
- Allotropic Forms, (a) Dissolve in a dry test tube a
small piece of roll sulphur in 3 to 5 cc. of carbon disulphide.
Pour the clear solution on a watch glass and allow it to evap-
orate spontaneously under the hood. Examine the crystals.
This is rhombic sulphur.
(6) Heat 10 grams of sulphur in a test tube until it has just
melted. Pour the liquid into the cone of a folded filter paper.
Then allow the melt to cool very slowly, and when it has par-
tially solidified, and a crust has formed over the surface,
break this crust and pour out what is still left in the liquid
state. Examine the crystals and compare them with those
observed in (a). This is monoclinic sulphur.
(c) Melt 10 grams of sulphur in a test tube. Heat slowly,
and observe all the changes that take place during the heating.
When the sulphur boils, pour it into a pan or large beaker
of water and observe the condition of the cooled product.
It will be found to be quite elastic. This is amorphous
sulphur.
Distinguish between the three solid forms of sulphur here ob-
served and discuss the differences in the conditions under which
they are formed (see reference book).
- Hydrogen and Sulphur, (a) Prepare hydrogen sul-
phide by the action of dilute sulphuric acid on ferrous sul-
phide in a generator bottle (see Note 13 (a), page 18). Pass
the gas through a drying tube containing a plug of cotton
wool, which retains any acid spray, then through a piece of
hard glass tube the end of which is drawn out into a capillary
jet. Heat a section of the tube to redness and observe that
a white deposit is formed on the walls of the cooler part of
the tube beyond.
(6) Light the gas issuing from the capillary jet and note
the products of the freely burning hydrogen sulphide. The
odor of sulphur dioxide is unmistakable. If a cold bottle
is held over the flame, water condenses inside the bottle. Now
thrust a piece of cold porcelain half way into the flame and
note the deposit of sulphur.
(c) Generate hydrogen gas in exactly the same way as
hydrogen sulphide in (a). Place about 0.5 gram of sulphur
