You are currently viewing Hydrogen : Properties, Preparation, Purification and uses

Hydrogen : Properties, Preparation, Purification and uses

Hydrogen :- History

Hydrogen was discovered by the German physician and natural scientist Paracelsus in the first half of the 16th century. In 1766, Henry Cavendish of England Scientist obtained this gas by the reaction of sulfuric acid on iron and zinc.

After studying its properties in detail gave it the name of flammable gas. In 1783, Lavosier obtained hydrogen gas from water. He made water by chemical combination of hydrogen and oxygen gas and named this gas hydrogen (Greek – Hydro = water, Gennao = generates).

Occurrence and Availability :

Hydrogen is found only in very small amounts in free form on Earth. It comes out with other gases during the eruption of volcano. This gas is also obtained from oil-wells during oil extraction. In combined state it is also found in water, acids, bases etc.

Hydrogen is the most abundant element in the universe. About half the mass of the Sun and most stars is made up of this gas. It makes up 1/9 of the mass of water. Hydrogen gas is present in all vegetarian, living thing, minerals and natural gas.

Methods of Preparation :

Laboratory Method :-

Hydrogen gas in the laboratory is prepared by the reaction of dilute sulfuric acid on zinc (granular).

Zn + H2SO4 ZnSO4 + H2

Material Required :-

Wolf bottle, thistle funnel, glass drain tube, perforated seat, trough, gas jar, granular pieces of zinc, dilute sulfuric acid and water.

Method :-

Putting pieces of granulated zinc in a Wolf bottle having two mouths, with the help of a cork, a thistle tube is placed in one mouth of the bottle and a drain tube in the other.

Hydrogen-preparation

The other end of the drain pipe is placed under the porous seat of a trough filled with water. Now with the help of thistle funnel, slowly pour dilute sulfuric acid into the wolf bottle. Chemical reaction starts as soon as sulfuric acid is applied to the pieces of zinc.

As a result of this reaction, the hydrogen wolf which comes out from the bottle in the beginning, the air inside the bottle is also mixed in it, so this gas is allowed to leave for some time. Then the gas jar filled with water is turned upside down and placed on the Water-tub and the hydrogen gas is collected by the downward displacement of the water in the gas jar.

Hydrogen

Precautions :-

  • The bottom end of the thistle funnel should be immersed in dilute sulfuric acid, otherwise hydrogen gas will escape from the thistle funnel.
  • The equipment must be airtight otherwise the gas will leak out.
  • Initially, some amount of gas is released from the water, then only after that the gas should be collected in the gas jar, because water vapor is found in the hydrogen gas that comes out in the beginning.
  • Do not bring any burning object near the equipment, as there is a risk of explosion.

Other method :-

Hydrogen gas can also be prepared with the help of water, acids and bases.

From water : -

By the reaction of water on different metals at ordinary temperature, metals like sodium, potessium and calcium etc.

2Na + 2H2O 2NaOH + H2

2K + 2H2O 2KOH + H2

Ca + 2H2O Ca(OH)2 + H2

By the reaction of water vapor on metals:

Metals like magnesium, zinc, iron, etc., after decomposition of hot water vapor give hydrogen gas.

Mg + H2O MgO + H2

Zn + H2O ZnO + H2

Precautions :-

First of all, take water in a round bottom flask and heat it. Iron powder is heated in a hard glass tube and the vapor formed in the flask is passed over the hot iron powder through the glass tube. In this way hydrogen gas is obtained –

3Fe + 4H2O ⇌ Fe3O4 + 4H2

By electrolysis of water :-