Difference between revisions of "Chlorine"

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'''Chlorine''' is the second-lightest [[halogen]], with the symbol '''Cl''' and atomic number 17. It has a sickly green colour and a distinctive smell, recognizable to many at low concentrations as 'the smell of pool centers' due to its compounds use as a water disinfecting agent.
+
'''Chlorine''' is the second-lightest [[halogen]], with the symbol '''Cl''' and atomic number 17. It has a sickly green colur and a distinctive smell, recognizable to many at low concentrations as 'the smell of pool centers' due to its use as a water disinfecting agent.
  
 
==Properties==
 
==Properties==
 
===Chemical===
 
===Chemical===
Chlorine is a strong oxidizer with 7 valence [[electrons]]. Its unstable [[electron configuration]] results in high reactivity. Because of this, chlorine usually exists on earth in the form of a [[halide]] [[salt]], and free chlorine is rare. Like [[fluorine]], elemental chlorine forms a highly reactive [[diatomic molecule|diatomic gas]].<ref>"Handbook of Toxicology of Chemical Warfare Agents", Academic Press, 2009, p. 313.</ref> Chlorine, like other halogens, forms many [[oxoanion|oxoanions]], negatively charged ions containing oxygen. Most notably, these are [[hypochlorite]](ClO<sup>-</sup>), [[chlorite]](ClO<sub>2</sub><sup>-</sup>), [[chlorate]](ClO<sub>3</sub><sup>-</sup>), and [[perchlorate]](ClO<sub>4</sub><sup>-</sup>).
+
Chlorine is a strong oxidizer with 7 valence [[electron]]s. Its unstable [[electron configuration]] results in high reactivity. Because of this, chlorine usually exists on earth in the form of a [[halide]] [[salt]], and free chlorine is rare. Like [[fluorine]], elemental chlorine forms a highly reactive diatomic gas.<ref>"Handbook of Toxicology of Chemical Warfare Agents", Academic Press, 2009, p. 313.</ref> Chlorine, like other halogens, forms many [[oxoanion|oxoanions]], negatively charged ions containing oxygen. Most notably, these are [[hypochlorite]](ClO<sup>-</sup>), [[chlorite]](ClO<sub>2</sub><sup>-</sup>), [[chlorate]](ClO<sub>3</sub><sup>-</sup>), and [[perchlorate]](ClO<sub>4</sub><sup>-</sup>).
  
 
Unlike hydrochloric acid, elemental chlorine easily corrodes copper, especially in moist air.<ref>[https://books.google.ro/books?id=KXwgAZJBWb0C&pg=RA1-PT224&lpg=RA1-PT224&dq=chlorine+attacks+copper&source=bl&ots=RgG_xtytXk&sig=AlZHGGUonD_edLw6r6tj7vpXE84&hl=ro&sa=X&ei=_zGYVMDIAqahyAP3_YCoDQ&ved=0CCkQ6AEwAQ#v=onepage&q=chlorine%20attacks%20copper&f=false Handbook of Corrosion Data, by Bruce D. Craig, David S. Anderson, p. 271]</ref>
 
Unlike hydrochloric acid, elemental chlorine easily corrodes copper, especially in moist air.<ref>[https://books.google.ro/books?id=KXwgAZJBWb0C&pg=RA1-PT224&lpg=RA1-PT224&dq=chlorine+attacks+copper&source=bl&ots=RgG_xtytXk&sig=AlZHGGUonD_edLw6r6tj7vpXE84&hl=ro&sa=X&ei=_zGYVMDIAqahyAP3_YCoDQ&ved=0CCkQ6AEwAQ#v=onepage&q=chlorine%20attacks%20copper&f=false Handbook of Corrosion Data, by Bruce D. Craig, David S. Anderson, p. 271]</ref>
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[[Potassium permanganate]] will oxidize [[hydrochloric acid]] to chlorine gas, as will [[manganese dioxide]]. In both cases, [[manganese(II) chloride]] will be produced as well.
 
[[Potassium permanganate]] will oxidize [[hydrochloric acid]] to chlorine gas, as will [[manganese dioxide]]. In both cases, [[manganese(II) chloride]] will be produced as well.
 +
 +
: 2 KMnO<sub>4</sub> + 16 HCl → 2 KCl + 2 MnCl<sub>2</sub> + 5 Cl<sub>2</sub> + 8 H<sub>2</sub>O
  
 
A hypochlorite and hydrochloric acid will produce chlorine; either a solution of [[sodium hypochlorite]] or [[calcium hypochlorite]]. A violent reaction with a lot of foam may take place in the case of the latter, and starting small scale is a must to get a sense for the reaction before any large scale chlorine production is attempted.
 
A hypochlorite and hydrochloric acid will produce chlorine; either a solution of [[sodium hypochlorite]] or [[calcium hypochlorite]]. A violent reaction with a lot of foam may take place in the case of the latter, and starting small scale is a must to get a sense for the reaction before any large scale chlorine production is attempted.
 +
 +
: MOCl + HCl → MCl + Cl<sub>2</sub> + H<sub>2</sub>O
  
 
A popular way of making chlorine on Sciencemadness is using hydrochloric acid and [[trichloroisocyanuric acid]] (TCCA). TCCA can be found as slow release chlorine tablets for swimming pools. This reaction is favorable because it not too expensive, produces a large amount of chlorine over an extended period of time (while hypochlorites tend to violently produce all the chlorine right on mixing with the acid), leaves no awful byproducts (such as [[Manganese dioxide|MnO<sub>2</sub>]]) and the reaction speed at standard concentrations and temperatures is not too fast nor too slow for most applications.
 
A popular way of making chlorine on Sciencemadness is using hydrochloric acid and [[trichloroisocyanuric acid]] (TCCA). TCCA can be found as slow release chlorine tablets for swimming pools. This reaction is favorable because it not too expensive, produces a large amount of chlorine over an extended period of time (while hypochlorites tend to violently produce all the chlorine right on mixing with the acid), leaves no awful byproducts (such as [[Manganese dioxide|MnO<sub>2</sub>]]) and the reaction speed at standard concentrations and temperatures is not too fast nor too slow for most applications.
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==Projects/Experiments==
 
==Projects/Experiments==
 
Chlorine can be used to produce anhydrous metal chlorides, such as [[Aluminium chloride|aluminum(III) chloride]], [[iron(II) chloride|iron(II)]] or [[iron(III) chloride]], and many others, which cannot be made in solution, due to formation of hydrates which are irreversible, and decompose to the metal oxide and HCl gas upon heating.
 
Chlorine can be used to produce anhydrous metal chlorides, such as [[Aluminium chloride|aluminum(III) chloride]], [[iron(II) chloride|iron(II)]] or [[iron(III) chloride]], and many others, which cannot be made in solution, due to formation of hydrates which are irreversible, and decompose to the metal oxide and HCl gas upon heating.
:2 Al + 3 Cl<sub>2 </sub> → 2 AlCl<sub>3</sub>
+
 
:2 Fe + 3 Cl<sub>2 </sub> → 2 FeCl<sub>3</sub>
+
: 2 Al + 3 Cl<sub>2</sub> → 2 AlCl<sub>3</sub>
 +
: 2 Fe + 3 Cl<sub>2</sub> → 2 FeCl<sub>3</sub>
  
 
Other projects:
 
Other projects:
 
*Make hypochlorites
 
*Make hypochlorites
*Make [[sulfur dichloride]]
+
*Make [[sulfur dichloride]] and [[disulfur dichloride]]
*Make [[disulfur dichloride]]
+
 
*Make interhalogen compounds
 
*Make interhalogen compounds
 
*Alkane halogenation
 
*Alkane halogenation
 +
*Element collecting
  
 
==Handling==
 
==Handling==
 
===Safety===
 
===Safety===
Elemental chlorine is extremely toxic and corrosive to many common metals. Because it is heavier than air, it tends to accumulate at the bottom of poorly ventilated spaces. Chlorine gas is a strong oxidizer, which may react with flammable materials. It is notorious for reacting with iron at high temperatures, in a strong exothermic reaction, known as chlorine-iron fire.
+
Elemental chlorine is extremely toxic and corrosive to mot materials, be it organic or inorganic. Because it is heavier than air, it tends to accumulate at the bottom of poorly ventilated spaces. It is highly irritant to eyes, mucous membrane, throat and lungs, even short term exposure may cause injury.
 +
 
 +
Chlorine gas is a strong oxidizer, which may react with flammable materials. It is notorious for reacting with iron at high temperatures, in a strong exothermic reaction, known as chlorine-iron fire.
  
 
===Storage===
 
===Storage===
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===Disposal===
 
===Disposal===
As it is toxic and has an irritating smell, it is recommended to neutralize chlorine before disposing of it. In gaseous form, elemental chlorine can be neutralized with ammonia, reaction that produces nitrogen gas and [[ammonium chloride]], though chloramines may also be produced as side products.
+
As it is toxic and has an irritating smell, it is recommended to neutralize chlorine before disposing of it. In gaseous form, elemental chlorine can be neutralized with ammonia at low concentrations, reaction that produces nitrogen gas and [[ammonium chloride]], though chloramines may also be produced as side products. This should not be used at high concentrations of chlorine in air, where chloramines may be produced in higher amount.
  
Aqueous chlorine however, should never be neutralized with ammonia, as it will generate toxic chloramines. Acids should also be avoided. Hydrogen peroxide will neutralize bleach and release oxygen. Ascorbic acid and its salts are also good at neutralizing chlorine. Other good neutralizing agents are certain sulfur compounds, such as bisulfites, metabisulfites, thiosulfites.
+
Aqueous chlorine however, should never be neutralized with ammonia, as it will generate toxic chloramines. Acids should also be avoided. Hydrogen peroxide will neutralize bleach and release oxygen. Ascorbic acid and its salts are also good at neutralizing chlorine. Other good neutralizing agents are certain sulfur compounds, such as sulfites, bisulfites, metabisulfites, thiosulfites.
 +
 
 +
==Gallery==
 +
<gallery widths="200" position="center" columns="4" orientation="none">
 +
Liquid_chlorine.jpg|A sample of liquid chlorine
 +
</gallery>
  
 
==References==
 
==References==
 
<references />
 
<references />
 
===Relevant Sciencemadness threads===
 
===Relevant Sciencemadness threads===
 +
*[http://www.sciencemadness.org/talk/viewthread.php?tid=9713 Chlorine - Illustrated Practical Guide]
 +
*[http://www.sciencemadness.org/talk/viewthread.php?tid=11259 Best overall chlorine generator?]
 +
*[http://www.sciencemadness.org/talk/viewthread.php?tid=22473 Making Chlorine]
 +
*[http://www.sciencemadness.org/talk/viewthread.php?tid=730 Preparation of Chlorine]
 +
*[http://www.sciencemadness.org/talk/viewthread.php?tid=17336 Small scale chlorine generation.]
 +
*[http://www.sciencemadness.org/talk/viewthread.php?tid=66003 Passing chlorine gas]
 +
*[http://www.sciencemadness.org/talk/viewthread.php?tid=24318 Found an easy way to make chlorine gas from muriatic acid and bleach]
 +
*[http://www.sciencemadness.org/talk/viewthread.php?tid=61768 Ways to get pure chlorine gas in a container/separate from the generator]
 +
*[http://www.sciencemadness.org/talk/viewthread.php?tid=66219 What to do with chlorine gas ?]
 +
*[http://www.sciencemadness.org/talk/viewthread.php?tid=29102 Storing Chlorine as a liquid?]
 
*[http://www.sciencemadness.org/talk/viewthread.php?tid=36860 Chlorine gas neutralization]
 
*[http://www.sciencemadness.org/talk/viewthread.php?tid=36860 Chlorine gas neutralization]
 +
 
[[Category:Elements]]
 
[[Category:Elements]]
[[Category:Halogens]]
 
[[Category:Oxidizing agents]]
 
 
[[Category:Diatomic elements]]
 
[[Category:Diatomic elements]]
[[Category:Gases]]
 
 
[[Category:Nonmetals]]
 
[[Category:Nonmetals]]
 +
[[Category:Halogens]]
 
[[Category:P-block]]
 
[[Category:P-block]]
 +
[[Category:Oxidizing agents]]
 
[[Category:Chlorinating agents]]
 
[[Category:Chlorinating agents]]
 
[[Category:Choking agents]]
 
[[Category:Choking agents]]
 +
[[Category:Gases]]

Latest revision as of 17:48, 8 November 2023

Chlorine,  17Cl
Chlorine ampoule.jpg
Chlorine gas in an ampoule.
General properties
Name, symbol Chlorine, Cl
Appearance Greenish gas
Chlorine in the periodic table
F

Cl

Br
SulfurChlorineArgon
Atomic number 17
Standard atomic weight (Ar) 35.45
Group, block , p-block
Period period 17
Electron configuration [Ne] 3s2 3p5
per shell
2, 8, 7
Physical properties
Pale green
Phase Gas
Melting point 171.6 K ​(−101.5 °C, ​−150.7 °F)
Boiling point 239.11 K ​(−34.04 °C, ​​−29.27 °F)
Density at  (0 °C and 101.325 kPa) 3.2 g/L
when liquid, at  1.5625 g/cm3
Critical point 416.9 K, 7.991 MPa
Heat of fusion 6.406 kJ/mol
Heat of 20.41 kJ/mol
Molar heat capacity 33.949 J/(mol·K)
 pressure
Atomic properties
Oxidation states 7, 6, 5, 4, 3, 2, 1, −1 ​(a strongly acidic oxide)
Electronegativity Pauling scale: 3.16
energies 1st: 1251.2 kJ/mol
2nd: 2298 kJ/mol
3rd: 3822 kJ/mol
Covalent radius 102±4 pm
Van der Waals radius 175 pm
Miscellanea
Crystal structure ​Orthorhombic
Thermal conductivity 8.9×10−3 W/(m·K)
Electrical resistivity >10 Ω·m (at 20 °C)
Magnetic ordering Diamagnetic
CAS Registry Number 7782-50-5
Discovery and first isolation Carl Wilhelm Scheele (1774)
· references

Chlorine is the second-lightest halogen, with the symbol Cl and atomic number 17. It has a sickly green colur and a distinctive smell, recognizable to many at low concentrations as 'the smell of pool centers' due to its use as a water disinfecting agent.

Properties

Chemical

Chlorine is a strong oxidizer with 7 valence electrons. Its unstable electron configuration results in high reactivity. Because of this, chlorine usually exists on earth in the form of a halide salt, and free chlorine is rare. Like fluorine, elemental chlorine forms a highly reactive diatomic gas.[1] Chlorine, like other halogens, forms many oxoanions, negatively charged ions containing oxygen. Most notably, these are hypochlorite(ClO-), chlorite(ClO2-), chlorate(ClO3-), and perchlorate(ClO4-).

Unlike hydrochloric acid, elemental chlorine easily corrodes copper, especially in moist air.[2]

Physical

Chlorine is a yellow-greenish gas, with a powerful odor similar to that of boiling hypochlorite solutions. It is heavier than air, and slightly soluble in water, 3.26 g/L.

Availability

While liquid (as in liquefied, and not aqueous solution) chlorine is sold by gas companies, it is hard to get hold of as it's very toxic and corrosive.

Chlorine is better produced from OTC products.

Production

There are many methods to generating chlorine gas, due to it being such a commonly used ion.

Potassium permanganate will oxidize hydrochloric acid to chlorine gas, as will manganese dioxide. In both cases, manganese(II) chloride will be produced as well.

2 KMnO4 + 16 HCl → 2 KCl + 2 MnCl2 + 5 Cl2 + 8 H2O

A hypochlorite and hydrochloric acid will produce chlorine; either a solution of sodium hypochlorite or calcium hypochlorite. A violent reaction with a lot of foam may take place in the case of the latter, and starting small scale is a must to get a sense for the reaction before any large scale chlorine production is attempted.

MOCl + HCl → MCl + Cl2 + H2O

A popular way of making chlorine on Sciencemadness is using hydrochloric acid and trichloroisocyanuric acid (TCCA). TCCA can be found as slow release chlorine tablets for swimming pools. This reaction is favorable because it not too expensive, produces a large amount of chlorine over an extended period of time (while hypochlorites tend to violently produce all the chlorine right on mixing with the acid), leaves no awful byproducts (such as MnO2) and the reaction speed at standard concentrations and temperatures is not too fast nor too slow for most applications.

Projects/Experiments

Chlorine can be used to produce anhydrous metal chlorides, such as aluminum(III) chloride, iron(II) or iron(III) chloride, and many others, which cannot be made in solution, due to formation of hydrates which are irreversible, and decompose to the metal oxide and HCl gas upon heating.

2 Al + 3 Cl2 → 2 AlCl3
2 Fe + 3 Cl2 → 2 FeCl3

Other projects:

Handling

Safety

Elemental chlorine is extremely toxic and corrosive to mot materials, be it organic or inorganic. Because it is heavier than air, it tends to accumulate at the bottom of poorly ventilated spaces. It is highly irritant to eyes, mucous membrane, throat and lungs, even short term exposure may cause injury.

Chlorine gas is a strong oxidizer, which may react with flammable materials. It is notorious for reacting with iron at high temperatures, in a strong exothermic reaction, known as chlorine-iron fire.

Storage

Liquefied chlorine must be stored in cold places, away from any source of heat. Chlorine can be liquefied at room temperature, at a pressure of 7.4 bar.

Chlorine releasing chemicals, such as bleach and TCCA should be stored in closed bottles, usually covered with a bag or in a box, that must be opened form time to time to release the pressure.

The storage area for both chemicals should not contain any metal parts susceptible to chlorine attack.

Disposal

As it is toxic and has an irritating smell, it is recommended to neutralize chlorine before disposing of it. In gaseous form, elemental chlorine can be neutralized with ammonia at low concentrations, reaction that produces nitrogen gas and ammonium chloride, though chloramines may also be produced as side products. This should not be used at high concentrations of chlorine in air, where chloramines may be produced in higher amount.

Aqueous chlorine however, should never be neutralized with ammonia, as it will generate toxic chloramines. Acids should also be avoided. Hydrogen peroxide will neutralize bleach and release oxygen. Ascorbic acid and its salts are also good at neutralizing chlorine. Other good neutralizing agents are certain sulfur compounds, such as sulfites, bisulfites, metabisulfites, thiosulfites.

Gallery

References

  1. "Handbook of Toxicology of Chemical Warfare Agents", Academic Press, 2009, p. 313.
  2. Handbook of Corrosion Data, by Bruce D. Craig, David S. Anderson, p. 271

Relevant Sciencemadness threads