Reactive Metal Fires?

Question

Choose which substance might be used in a fire-retarding agent for combating each of the following fires

Choose From The Following 4 To Estinguish The Flame

1.Water
2. Carbon Dioxide
3. Silicon Dioxide
4. Carbon Tetrachloride

1.When Lithium Burns In Air?
2. When Potassium Burns In Air?
3. When Sodium Burns In Air?

Heats Of Formation For Help..
Li2O(s) -597.9 Li+(aq) -278.5
Na2O(s) -416 Na+(aq) -240
K2O(s) -361 K+(aq) -251
CO(g) -110.5 CO2(g) -393.5
H2O(l) -286 OH-(aq) -230
CCl4(l) -135 SiO2(s) -911
LiCl(s) -409 NaCl(s) -411
KCl(s) -436 Cl-(aq) -167

Answer 1

Definitely not water, as those three metals will burn on contact with water (and potassium will explode.) Liquid CO2 might do, as it would cool the burning material extensively, possibly below the ignition point. The sand (SiO2) would be a smothering agent. I'm not sure about the carbon tet.

5 NOV 06, 1522 hrs, GMT.