Q.Saline hydrides are known to react with water violently producing fire. Can CO2, a well known fire extinguisher, be used in this case? Explain.

Saline (ionic) hydrides, such as NaH and CaH2, react violently and exothermically with water, liberating flammable dihydrogen gas and generating enough heat to ignite it:

A normal fire would be smothered by CO2, which works by cutting off the oxygen supply and is inert towards ordinary combustible materials. However, ionic hydrides contain the hydride ion H⁻, which is a powerful reducing agent. Rather than being inert to CO2, the hydride can itself chemically react with and reduce carbon dioxide (H⁻ can reduce carbon in CO2, analogous to how strong reducing hydrides reduce many oxidising species), so CO2 does not behave as an inert blanketing gas in this situation — it participates in a further reaction with the very reactive hydride/metal system. …

Recall that saline hydrides are strong reducing agents (via H⁻); reason that CO2, rather than acting as an inert blanket as it does for normal fires, can itself be attacked/re …

• Assuming CO2 extinguishers work universally on all fires — they fail specifically here because the fuel (ionic hydride) is reactive enough to attack CO2 itself. …