(Hydrogen propellant tanks) can be liquid.Logical formLearned from2 sentences. A (hydrogen gas) can be red.Logical formLearned from2 sentences. Pressure may pertain-to a liquid hydrogen.Logical formLearned from2 sentences. Stars may show (emission lines) of hydrogen.Logical formLearned from2 sentences. A (hydrogen fluoride) may be generated during a (chemical reaction).Logical formLearned from2 sentences. A (hydrogen bomb) may be detonated.Logical formLearned from2 sentences. Bonds can be between (hydrogen atoms).Logical formLearned from2 sentences. Some engines may burn liquid hydrogen.Logical formLearned from2 sentences. (Hydrogen cyanide) can be explosive.Logical formLearned from2 sentences. The universe may be made of hydrogen.Logical formLearned from2 sentences. A mass may pertain-to a neutral hydrogen.Logical formLearned from2 sentences. A reaction can be between (hydrogen peroxide).Logical formLearned from2 sentences. A frequency may pertain-to a (hydrogen spin-flip transition).Logical formLearned from2 sentences. (Hydrogen ions) may be exchanged for sodium.Logical formLearned from2 sentences. (Hydrogen sulfide) may accumulate.Logical formLearned from2 sentences.