Answer
Ans: -1.Highly asphyxiating g as, 9% conc. Can cause unconsciousness within minutes(toxic). 2.Very little cooling effect so there is danger to re-ignite.
3.Once released, there is no second option available so 100% sealing is required before release. 4. Compulsory evacuation.
5. ME out of operation.
6. One time use.