What Is Hydrogen Gas?
Hydrogen is one of the elementary substances in the form of a gas. It has no color or taste or odor, so we can neither see, smell nor taste it. It is the lightest substance known to the world. We have by the aid of chemistry been able to catch and retain it in sufficient quantities to weigh it and have found it to be lighter than anything else in the world. It is soluble in water and some other liquids, but only slightly so. It refracts light very strongly and will absorb in a very remarkable manner with some metals when they are heated. It burns with a beautiful blue flame and very great heat. When burned it combines with oxygen in the air and forms water. Hydrogen is not poisonous but, if inhaled, it prevents the blood from securing oxygen, and so the inhaling of hydrogen will cause death. Hydrogen is not found free in the air except in small quantities like oxygen and nitrogen and is, therefore, secured by separating compounds by known methods. It can be secured by the action which diluted sulphuric acid has on zinc or iron, by passing steam through a red-hot tube filled with iron trimmings, by passing an electric current through water and in other ways. Hydrogen is absolutely necessary to every form of animal or vegetable structure. It is found in all acids.