Hydrogen is the lightest of all the elements. There is very little hydrogen in the earth’s atmosphere. Hydrogen is so light that its molecules are not held by the earth’s gravity and they diffuse into space.
Overall, it is the most common element in the universe. It is probable that is forms about 90% of the total mass of the universe. It is believed that the sun composes almost of hydrogen and helium.
Hydrogen occurs naturally in air as hydrogen gas. It also occurs in combined state in water, acids, petroleum, and natural gas and in almost all organic substances (proteins, carbohydrates, fats, etc.).
Uses of Hydrogen Gas
State uses of hydrogen gas
1. It is used in the manufacture of ammonia by the Haber process, which is based on the direct combination of hydrogen and nitrogen.
2. It is used in the hardening of vegetable oils to make margarine.
3. It was formerly used for inflating balloons and air ships. But hydrogen is inflammable and many accidents occurred. Its use has been replaced by helium (another gas occurring in air). Nowadays, hydrogen is used by meteorologists to fill weather balloons, which carry weather instruments that record information on various elements of weather in the upper atmosphere.
4. It is used to prepare water gas, which is used as a fuel for space rockets. When hydrogen contained in water gas is burned in air, it produces extremely high heat energy that is used to power rocket engines.
5. It is used in welding by the atomic hydrogen torch. The complete combustion between hydrogen and oxygen is a highly exothermic reaction and can produce an oxy-hydrogen flame that has a temperature of nearly 2000ºC, and is therefore useful in the welding and cutting of metals. However, the explosive nature of the combustion of hydrogen with oxygen makes the use of oxy-hydrogen flame less favourable than the oxyacetylene flame.
6. It is used in the synthesis of hydrochloric acid. In this case, hydrogen combines directly with chlorine to form hydrogen chloride gas.
The hydrogen chloride gas is then dissolved in water to form hydrochloric acid.
7. It is used in the manufacture of methanol (wood spirit). In this process hydrogen combines directly with carbon monoxide.