2. What’s in a name ?
The name Chlorine comes from the Greek word ‘’
khloros’’ , meaning greenish-yellow.
This was in reference to the color of chlorine gas.
Chlorine gas in a glass →
www.google.com
3. History
Although history has it that compounds
containing chlorine such as sodium
chloride were discovered and were in use
as far back as 300BC, Chlorine was first
synthesized by a Swedish chemist
called Carl Wilhem Scheele in 1774. 1
4. How did it happened ?
After releasing a few drops of hydrochloric acid onto a
piece of Manganese dioxide, He observed the
evolution of a greenish- yellow gas a few seconds later,
having no idea that he had just discovered a gas
MnO2 + 4 HCl ==> Cl2 + MnCl2 + 2 H2O
5. However, it was not until 1810 when Sir Humphrey
Davy, an English chemist, through a series of
experiments, discovered that chlorine was actually an
element.
In 1810 ,Davy named the element ‘’Chloric gas ‘’ or
Chlorine from the greek word ‘khloros ‘ ( greenish-
yellow gas )
6. The ubiquitous Chlorine !!
Chlorine is one of the most abundant chemical
elements on earth.
It is found abundantly in almost every part of the
earth. I t can be found in soils, plants ,animals. Sea
water also serves as a huge source of chlorine.
Due to the highly reactive nature of chlorine, it is
usually not found in its free elemental form . It is
usually found combined with other elements.
7. The most common chlorine compound is sodium
chloride (NaCl ), which is also commonly known as sea
salt. NaCl occurs in sea water and in rock salt.
8. The identity of chlorine
At room temperature, Chlorine is a pungent-smelling ,
poisonous greenish -yellow gas which also fumes in
moist air . It has the following properties :
Atomic Number : 17
Atomic Mass : 35.453
Melting Point : -101 degrees Celsius
Boiling Point : -35 degrees Celsius
Density : 0.003
9. Chlorine is manufactured industrially as a by-product
in the manufacture of Caustic Soda by the electrolysis
of sodium chloride, as depicted by the reaction:
electricity + 2 NaCl + 2 H2O ==> Cl2 + H2 +
2 NaOH
10. How useful is chlorine ?
Well, as it turns out, chlorine has countless
uses, chances are you use it everyday !
Chlorine is the 9th largest chemical produced in the
United States by volume. 2 This underscores the
numerous uses of Chlorine. As an element, chlorine
is used to :
Manufacture hydrochloric acid by the direct reaction
with hydrogen gas :
H2O + Cl2 ==> HCl + HClO
11. Synthesize a wide range of organic compounds such as
Methylene Chloride,( CH2Cl2), Chloroform, (CHCl3),
Carbon Tetrachloride, CCl4.
Extract Gold from its ores.
12. In combination with other compounds , chlorine has a
wide variety of uses including :
manufacture of bleaching powder and liquid bleaches
preparation of insecticides, plastics , paints and
aerosols.
As a disinfectant in the treatment of water for
domestic consumption.
Treatment of pool water
As a key component of cancer –fighting drugs.
13. DID YOU KNOW…?
Chlorine constitutes about 0.013 percent of the Earth's
crust.
Chlorine gas, a poison, was the first gas used in
chemical warfare in World War I. It was used as a
choking agent.
Chlorine itself is not flammable, but it can react
explosively or form explosive compounds with other
chemicals such as turpentine and ammonia.
14. Household chlorine bleach can release chlorine gas if
it is mixed with other cleaning agents.
The water you drink everyday is treated with chlorine.
15. Just for laughs !!!
Don’t try this at home !
http://www.myspace.com/video/jango-feit/chlorine-
bombs/3301351
Chlorine can be really dangerous when mixed with other
stuff !!
16. References :
1. American Chemistry council home page
http://chlorine.americanchemistry.com/chlorinestory
(accessed Nov 12, 2011 ).
2. Donald, O. ; ‘’chlorine’’
http://www.ucc.ie/academic/chem/dolchem/html/ele
m017.html (accessed Nov 14, 2011).
