A garage that specializes in foreign cars had a small magnesium fire when a car part was ignited. The mechanic knew from his training that he should not use water but could use a dry powder like a sodium chloride based fire extinguishing powder (MET-L-X) or a graphite based (LITH-X). He knows that the CO2 extinguishing powder is not a good choice.
- Explain the reasons why the mechanic thinks using CO2 is not a good idea.
- If MET-L-X or LITH-X is used, a residue could be left on the metal and if cleaned with water, the fire may be rekindled. Explain the chemical process involved in this phenomenon for both types of fire extinguishing powder.