calcium carbide*
carbide
|
11-12
1
2
3
-
5
-
-
|
4.3
Not Hazardous
|
II
|
1402
75-20-7
|
Toxic by all routes of exposure. Evolves highly flammable acetylene gas on contact with water; do not inhale fumes. Use in a fume cupboard if practicable; otherwise use small quantities in a well-ventilated area. Use eye and skin protection when splashes are possible. To demonstrate acetylene combustion use an old "carbide" lamp outside the classroom in the open air. Ensure that the seals on the lamp are serviceable. Alternatively, in a fume cupboard, place a lump (2-3 g) of calcium carbide into a 250 mL beaker with 50 mL of water.
The resulting bubbles of acetylene can be ignited. The gas has a foul smell due to the presence of trace quantities of phosphorus hydrides. Beware of dangerously explosive mixtures of acetylene and air. Use large lumps of material rather than fine powder, since reaction with water is slower and more controllable. Acetylene should not be reacted with aqueous silver or copper(I) salts, since explosive acetylides are formed.
Q-Stores
32
See also REDUCTANTS.
and Appendix F.
|
