Why is calcium carbide mixed with sand?
Calcium carbide (CaC2) reacts with water to produce acetylene (C2H2):
CaC2(s)+2H2O(g)Ca(OH)2(s)+C2H2(g)
When it is used to produce acetylene, however, it is mixed with sand because the reaction between CaC and HO is quite exothermic and this causes two issues:
- the as-produced acetylene is very flammable;
- the Ca(OH) byproduct.
Both can be circumvented by adding sand to the reaction mixture in order to absorb the heat excess and let calcium hydroxide react with it to form calcium...