Chlorine

=__Chlorine__=

Facts

 * It is the second most abundant Halogen, and 21st most abundant chemical element in the Earth's crust.
 * Chlorine is commonly found in table salt, swimming pools, and cleaning products.
 * During World War I, Chlorine was first used as a weapon. Bertholite, Chlorine gas, was used by the Germans because when soldiers inhaled the gas, it would react with the water in the mucus in the lungs and form hydrochloric acid. Hydrochloric acid can be very lethal in large amounts.
 * Chlorine gas is easily dissolved in water forming hydrochloric acid and hypochlorous acid aqueous solution. Chlorine gas is poisonous because it's very reactive. In a chemical lab chlorine gas is always prepared by treating hydrochloric acid (high concentration) with manganese dioxide. Sodium hydroxide solution is used to deal with the remaining chlorine gas after the experiment, according to the following equation 2 NaCl + 2 H 2 O → Cl 2 + H 2 + 2 NaOH. Chlorine gas can react with hydrogen gas in a combustion reaction producing chlorine hydride gas.



//**Chlorine History**//
- The most common compound of chlorine, sodium chloride, has been known since ancient times; archaeologists have found evidence that rock salt was used as early as 3000 BC and brine as early as 6000 BC. Around 1630, chlorine was recognized as a gas by the Belgian chemist and physician [|Jan Baptist van Helmont]. Carl Wilhelm Scheele Elemental chlorine was first prepared and studied in 1774 by Swedish chemist [|Carl Wilhelm Scheele], and, therefore, he is credited for its discovery. He called it "//dephlogisticated muriatic acid air//" since it is a gas (then called "airs") and it came from [|hydrochloric acid] (then known as "muriatic acid"). However, he failed to establish chlorine as an element, mistakenly thinking that it was the [|oxide] obtained from the hydrochloric acid (see [|phlogiston theory]). He named the new element within this oxide as //muriaticum//. Regardless of what he thought, Scheele did isolate chlorine by reacting [|MnO2] (as the mineral [|pyrolusite]) with HCl: 4 HCl + MnO 2 → MnCl 2 + 2 H 2 O + Cl 2 Scheele observed several of the properties of chlorine: the bleaching effect on [|litmus], the deadly effect on insects, the yellow green color, and the smell similar to [|aqua regia].

At the time, common chemical theory was: any acid is a compound that contains oxygen (still sounding in the German and Dutch names of [|oxygen]: //sauerstoff// or //zuurstof//, both translating into English as //acid stuff//), so a number of chemists, including [|Claude Berthollet], suggested that Scheele's //dephlogisticated muriatic acid air// must be a combination of oxygen and the yet undiscovered element, //muriaticum//.

Chlorine has a melting point of 172.2 (K). Chlorine has a boiling point of 238.6 (K). Chlorine is a halogen.


 * Symbol:** Cl **Atomic Number:** 17 **Atomic Mass:** 35.4527 amu **Melting Point:** -100.98 °C (172.17 K, -149.764 °F) **Boiling Point:** -34.6 °C (238.55 K, -30.279997 °F) **Number of Protons/Electrons:** 17 **Number of Neutrons:** 18 **Classification:** Halogen **Crystal Structure:** Orthorhombic **Density @ 293 K:** 3.214 g/cm3 **Color:** green

Isotopes

 * ** Isotope ** || ** Half Life ** ||
 * Cl-35 || Stable ||
 * Cl-36 || 301000.0 years ||
 * Cl-37 || Stable ||
 * Cl-38 || 37.2 minutes ||

Facts

 * Date of Discovery:** 1774 **Discoverer:** Carl Wilhelm Scheele **Name Origin:** From the Greek word //khlôros// (green) **Uses:** Water purification, bleaches **Obtained From:** Salt

Chlorine Risks chlorine is found in pools
 * **Rapid aging of the skin**
 * • Gastrointestinal problems**
 * • Increased heart pressure**
 * • Hazard for liver disease**
 * • Increase risk of stroke**