The NFPA health rating for pure sodium thiosulfate is 1. Why is the NFPA health
ID: 534764 • Letter: T
Question
The NFPA health rating for pure sodium thiosulfate is 1. Why is the NFPA health rating for the sodium thiosulfate + NaOH solution 3?
1. It is prepared in a solution containing ethyl alcohol
2. The compound becomes more toxic when dissolved in water
3. It is prepared in a solution containing sodium hydroxide
4. The compound decomposes when exposed to light, making it more toxic
1. It is prepared in a solution containing ethyl alcohol
2. The compound becomes more toxic when dissolved in water
3. It is prepared in a solution containing sodium hydroxide
4. The compound decomposes when exposed to light, making it more toxic
Explanation / Answer
It is because sodium thiosulfate +NaOH are easily capable of explosive decomposition when exposed to light or react with water. Thus, making it more toxic. Therefore health rating is 3 according to NFPA.
So, option (2) and (4) both are correct choices.