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How explosive is hydrogen on its own? Eg if I light a match to a hydrogen leak in air, how bad would it be? I thought it would just burn, without a pure oxygen

How explosive is hydrogen on its own? Eg if I light a match to a hydrogen leak in air, how bad would it be? I thought it would just burn, without a pure oxygen counterpart. So comparable to petrol.

rwmj 4y ago
One memorable chemistry lesson at my school[1] involved the teacher bubbling hydrogen through soapy water, while a student stood on the bench with a lighted splint and set fire to the bubbles of hydrogen floating up. They didn't explode so much as rapidly burned. (Of course they didn't mix much with air first, probably if the bubbles had mixed air/H2 they would have exploded more?) [1] Health and safety wasn't much of a concern back then. I also remember another lesson where we lined up and plunged our fingers into a beaker of mercury. Quite a weird feeling.
aaaaaaaaaaab 4y ago
https://www.youtube.com/watch?v=6X7bbxOUExU https://www.youtube.com/watch?v=6X7bbxOUExU
- rich_sasha 4y ago
  That's a pure hydrogen-oxygen mix and with optimal ratio.
jrootabega 4y ago
There will be better, more factual answers. But when I was about 10 we had a science show at school where they lit two balloons on fire - one with air or helium and one with hydrogen. They were about .7 meters in diameter. The second time the show came to our school, I knew what was coming with the hydrogen balloon, and, hating sudden loud noises, excused myself to the bathroom until it was over. I think I stayed there about 15 minutes before they had to come check on me. So at least 15 10-year-old-bathroom-minutes explosive. In short, very loud. But if they do it repeatedly in front of a hundred children, probably not too much. I don't remember feeling any pressure wave. But I'm guessing that a hydrogen leak in an enclosed space could easily result in a dangerous H2/O2 mixture.
- rich_sasha 4y ago
  Interesting story! I take it it was much louder than just a popping balloon? I guess the "enclosed spaces" case matters for eg underground parking, maybe less in roads.
  - jrootabega 4y ago
    Oh yeah, it was brutally loud. At least to a 10-year-old.

How explosive is hydrogen on its own? Eg if I light a match to a hydrogen leak in air, how bad would it be? I thought it would just burn, without a pure oxygen counterpart. So comparable to petrol.

rwmj 4y ago

One memorable chemistry lesson at my school[1] involved the teacher bubbling hydrogen through soapy water, while a student stood on the bench with a lighted splint and set fire to the bubbles of hydrogen floating up. They didn't explode so much as rapidly burned. (Of course they didn't mix much with air first, probably if the bubbles had mixed air/H2 they would have exploded more?) [1] Health and safety wasn't much of a concern back then. I also remember another lesson where we lined up and plunged our fingers into a beaker of mercury. Quite a weird feeling.

aaaaaaaaaaab 4y ago

https://www.youtube.com/watch?v=6X7bbxOUExU https://www.youtube.com/watch?v=6X7bbxOUExU

rich_sasha 4y ago
That's a pure hydrogen-oxygen mix and with optimal ratio.

jrootabega 4y ago

There will be better, more factual answers. But when I was about 10 we had a science show at school where they lit two balloons on fire - one with air or helium and one with hydrogen. They were about .7 meters in diameter. The second time the show came to our school, I knew what was coming with the hydrogen balloon, and, hating sudden loud noises, excused myself to the bathroom until it was over. I think I stayed there about 15 minutes before they had to come check on me. So at least 15 10-year-old-bathroom-minutes explosive. In short, very loud. But if they do it repeatedly in front of a hundred children, probably not too much. I don't remember feeling any pressure wave. But I'm guessing that a hydrogen leak in an enclosed space could easily result in a dangerous H2/O2 mixture.

rich_sasha 4y ago
Interesting story! I take it it was much louder than just a popping balloon? I guess the "enclosed spaces" case matters for eg underground parking, maybe less in roads.
- jrootabega 4y ago
  Oh yeah, it was brutally loud. At least to a 10-year-old.