OXIDIZING ACTION OF SULFUR DIOXIDE Submitted by: Paul RI. Lauren, Forest Hills High School, Forest Hills, N. Y. Checked bw: Edward J. Hoouer " .. and James W. Price, NSF Chemistry Institute. Montana State College, Bozeman. Mont.
PREPARATION
Provide a dry erleumeyer flask (500-ml), magnesium ribbon, CSz, dil HC1, and a source of dry Sot.
orating. Observe any residue. Add dil HC1 to the residues and to the flask
DEMONSTRATION
REMARKS
By air displacement fill a dry 500-ml erlenmeyer flask with dry SO2 in a hood. Place the flask on the lecture table. Using tongs drop a l'/z in. length of burning magnesium ribbon into the flask and quickly recork. Voluminous white smoke is produced. After the smoke has settled return the flask to the hood and open the flask to vent the excess SO2. A yellow deposit is visible on the unburned magnesium near the end where burning took place. Add CS2 to this deposit and to the contents of the flask. Pour +,heCS, solutions onto separate watch glasses for evap-
The voluminous smoke is indicative of the formation of a considerable amount of solid particles. At the high temperature it is likely that the smoke consists of a complex mixture of substances, such as sulfur, NgS, NgO, MgSOa, etc. A hand lens shows the residues from the evaporated CSz solutions to have t,he appearance of sulfur. Hydrogen sulfide is not detected when these residues are t,reated with dil HCI. The odor of H2S is noticeable, however, when HC1 is added to the contents of the flask, indicating the presence of a sulfide. Journal o j Chemical Educnlion . Jonl~ary 1.969
Volume
46, Number 1 , January 1969
/
A55
