Saline hydrides are known to react with water violently producing fire. Can CO2, a well
known fire extinguisher, be used in this case? Explain
I have three answers. Which answer is correct? I think second and third answers are same.
Answer1:- Saline hydrides (example: NaH, LiH, etc.) on reaction with water to form a base and
hydrogen gas.
The chemical equation used to represent the reaction can be written as:
MH(s) + H₂O(aq) → MOH(aq) + H₂(g)
The above reaction is very violent and produces fire.
Carbon dioxide (CO₂) is heavier than dioxygen. It is used in fire extinguisher because it
covers the fire as a blanket and inhibits the supply of dioxygen, thereby dousing the fire.
CO₂ can be used in this case as well. It is heavier than hydrogen gas and will be effective
in isolating the burning surface from dihydrogen and dioxygen.
Answer 2:-
Answer 3:-
No. Because if saline hydrides react with water the reaction will be highly exothermic thus the hydrogen evolved in this case can catch fire. C02 cannot be used as fire extinguisher because C02 will get absorbed in alkali metal hydroxides.
Reaction of saline hydride with water
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Reaction of saline hydride with water
Last edited by Dhamnekar Winod on Fri Mar 05, 2021 10:06 am, edited 1 time in total.
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Re: Reaction of saline hydride with water
Number 2 is only right. NaH reduces everything. So also CO2 to get Carbon, water and hydroxide.