Knowladage of hydrogen

1. 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,
Lavoisier 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).
Md.Arifull Hoque Shaheen
Diploma In Chemical Engineering

2. 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.
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.
Zn + H2SO4 → ZnSO4 + H2

3. Metals like
magnesium, zinc,
iron, etc., after
decomposition of
hot water vapor
give hydrogen gas.
Mg + H2O → MgO +H2
Zn + H2O → ZnO + H2
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

4. By Electrolysis of
Water: Where
electricity is cheap, it is
used there. Hydrogen
gas in excess of acid or
base mixed water is
collected by the method
of electrolysis at the
cathode.
H2O ⇌ H+ OH–
H+ + e– → H
H + H → H2
OH– – e– → OH
4OH → 2H2O + O2

5. Uses of Hydrogen :-
Hydrogen is used by Haber method to obtain
ammonia.
It is used in making hydrochloric acid and
vegetable ghee.
It is used for joining and cutting metals by
generating oxyhydrogen flame (2800°C
temperature).
It is also used as a reducing agent.
Earlier it was used in balloons, but now a
mixture of helium and hydrogen is used in its
place.
Used in the synthesis of mthenol.
CO + H2 + H2 → CH3OH
Hydrogen gas is used to make water gas (CO +
H2).
With the help of hydrogen coal, it is used to
make artificial petrol.
Physical properties :-
● It is soluble in water in very
small amounts.
● It is absorbed by metals like
platinum and palladium.
● It is a good conductor of heat.
● It is a lighter gas than all other
gases and the mass of 1 ml
hydrogen gas at S.T.P. is
0.00009 grams.
● Hydrogen gas can be liquefied at
low temperature (-253°C) and
high pressure.
● Hydrogen gas burns by itself,
but does not help in the burning
of other things.
● Its relative density is 0.0695.
● Hydrogen gas is colourless,
odourless, tasteless and
transparent.