Is hydrogen explosive?
If you had a tank of hydrogen in space, and you added energy by heating the gas, nothing would happen until the pressure of the gas exceeded the hold capacity of the tank. So, no, in an atmosphere where there are no other atoms or molecules, hydrogen might not be regarded as explosive. However, what we usually mean is “Here on earth, in our normal atmosphere, if I spray some hydrogen (or gasoline, or water, or whatever) on a flame, will it explode?” This question should be phrased as a chemistry question: If hydrogen is exposed to a flame (or in some other way has energy added) in the presence of Oxygen, will there be a chemical reaction which gives off energy (i.e. is exothermic)? The answer to that question is, yes, definitely!!! Hydrogen molecules and Oxygen molecules have a much lower energy state when combined to make the molecule H2O (water) than the total energy when they are separate molecules of hydrogen (H2) and Oxygen (O2). There is plenty of Oxygen in the atmosphere here on
