Preparation Of Hydrogen Gas

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Symbol - H

Atomic No :1

Atomic wt : 1.008

Electronic Configuration :1s1

Oxidation Nos : (+1),(-1)

In 1660 Robert Boyle first prepared hydrogen by the action of iron powder and dilute mineral acid,Henry Cavendish was the first to atudy the properties of this gas and named it 'inflamable air'.In 1783 Lavoisier proved hydrogen to be an element and named hydrogen.

Hydrogen is found to occur in the atmosphere of the sun.It is also found in air in very small amount(about 1 ppm).combination with other elements it is found in fats and oils,coal,water,acids,alkalis and in most organic compounds like hydrocarbons.

The position of hydrogen in the periodic table :

Hydrogen is the first member of elements in the periodic table as its atomic number is 1.Its position in the periodic table is still anomalous due to its duel behaviour.It has only one electron in 'K' shell which can accomadate at maximum 2 electrons.It has therefore the tendency to gain or lose electrons.

Laboratory methods of preparation of Hydrogen gas

1) By the action of Acids on Metals :

Metals like ...
... Li,Na,Ca, etc. placed above hydrogen in electrochemical series when treated with acids like HCL or dil. H2S04 evolve hydrogen gas

Aim : Preparation of hydrogen

Apparatus required : Round bottomed flask , delivery tube , stand ,double split cork, thistle funnel

Chemicals required : zinc granules, dil. Sulphuric acid or hydrochloric acid

Zn + dil. H2SO4 = ZnSO4 + H2

hydrogen

Other methods of preparation of Hydrogen Gas :

2) By the Action of Alkalies on Amphoteric metals.

3) By the Action of water on Active metals (Metals placed above electrochemical series)

4) By the Action of water on Metal Hydride

Industrial methods of preparation of Hydrogen gas

1) By the electrolysis of water containing a small amount of Acid or Alkali :

Water is a weak electrolyte(does not dissociate completely).When an electrolyte(acid, base or a salt) is added to water which is a weak electrolyte , it conducts electricity. When electricity is passed, water dissociates into positive and negative ions(anions and cations). Hydrogen gas is collected at cathode and oxygen at anode.

Check this Formula for Ideal Gas Law awesome i recently used to see.

2H2O ----- 2H2 + O2

Other methods of preparation of Hydrogen Gas :

2) From water gas by Bosch process

3) From Natural gas mixed with steam

There are a number of different methods from which hydrogen gas can be produced. These include industrial methods of preparation, general methods of preparation, and laboratory methods of preparation of Hydrogen gas. This variety of feasable methods available as different options for the production of Hydrogen gas itself reflects the large number of compounds that contain Hydrogen, and hence the reactivity of Hydrogen.
Hydrogen gas is a diatomic gas. It is included in the activity series of metals because it forms positively charged ions. Out of the many methods of hydrogen gas production, the important ones are discussed below.

Hydrogen gas production Bosch process

Bosch process

This is the industrial method of production of Hydrogen gas. It is called as the Bosch process after the scientist who invented it. In the Bosch process, Carbon and Steam are reacted at temperature as high as 1000 degrees Celcius. This results in the production of a mixture of Carbon monoxide and Hydrogen gas:

C + H2O - [CO + H2]

This resultant mixture is called as water gas, and it has wide industrial use. To separate Hydrogen from Carbon monoxide gas, the mixture (water gas) is passed through another chamber containing steam at a temperature of 450 degrees Celsius. This results in the production of Carbon dioxide and Hydrogen.

[CO + H2] + H2O - CO2 + 2H2O

The final mixture contains Carbon dioxide, Hydrogen and traces of unreacted carbon monoxide. To remove carbon dioxide, the mixture is passed through caustic potash solution, and to remove carbon monoxide impurity, the mixture is passed through Ammoniacal copper chloride solution.

hydrogen gas production laboratory method

Action of steam on less active metals like magnesium, zinc, aluminium and iron

Proceedure: Place a few pieces of zinc granules in a flat bottom flask and add dilute Hydrochloric acid to it drop by drop. Fix a delivery tube in the cork of this flask which can carry the Hydrogen gas produced out of the flask.

The Hydrogen gas obtained through the delivery tube is collected through downward displacement of water.

Zn + 2HCl - ZnCl2 + H2

Action of cold water on highly active metals like sodium, potassium and calcium

On adding small pieces of these highly reactive metals, (sodium, potassium and calcium), to cold water, they are able to displace the Hydrogen atoms present in the molecules of water to liberate Hydrogen gas and form their respective alkalis.

Na + H2O - NaOH + H2

K + H2O - KOH + H2

Ca + 2H2O - Ca(OH)2 + H2

Note:- In this reaction only small pieces of the metals are to be taken and they are only to be added into a beaker full of water as they result in exothermic reactions, which can cause the metal to jump upwards.

Learn more on about Radio Wave Frequency and its Examples. Between, if you have problem on these topics Mole Chemistry, Please share your comments.