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
HistoryAlthough 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
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 gasMnO2 + 4 HCl ==> Cl2 + MnCl2 + 2 H2O
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 )
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.
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.
The identity of chlorineAt 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
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
How useful is chlorine ?Well, as it turns out, chlorine has countlessuses, 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
Synthesize a wide range of organic compounds such as Methylene Chloride,( CH2Cl2), Chloroform, (CHCl3), Carbon Tetrachloride, CCl4. Extract Gold from its ores.
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.
DID YOU KNOW…? Chlorine constitutes about 0.013 percent of the Earths 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.
Household chlorine bleach can release chlorine gas if it is mixed with other cleaning agents. The water you drink everyday is treated with chlorine.
Just for laughs !!!Don’t try this at home ! http://www.myspace.com/video/jango-feit/chlorine- bombs/3301351Chlorine can be really dangerous when mixed with other stuff !!
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).