Sodium is a silver-colored metal which is soft enough to reduced with aknife. It is very reactive metal, and is constantly found normally inionic compounds, no in the pure metallic form. Pure sodium metal reactsviolently (and occasionally explosively) with water, producing sodium hydroxide,hydrogen gas, and also heat:
2Na(s) + 2H2O(l) ——>2NaOH(aq) + H2(g)
Chlorine is apoisonous, yellow-green gas, with a very sharpodor, and also was offered in gas war during world War I.
You are watching: Potassium metal is exposed to an atmosphere of chlorine gas.
Sodium and also chlorine react with each other, however, to develop a substancethat is acquainted to virtually everyone in the world: sodium chloride,or table salt:
2Na(s) + Cl2(g) ——>2NaCl(s)
It is straightforward to check out why this reaction takes ar so readily as soon as we look at iton an atomic level: sodium has actually one electron in its outermost (valence)shell, if chlorine has seven electron in its valence shell. As soon as asodium atom move an electron come a chlorine atom, creating a sodium cation(Na+) and a chloride anion (Cl-), both ions have actually completevalence shells, and are energetically an ext stable.
The reaction is very exothermic, developing a glowing yellow light and agreat deal of heat energy.
In the complying with demonstrations, a 2.5 liter bottle is filled through chlorinegas. A coating of sand top top the bottom that the party absorbs some of theheat energy developed during the reaction, and also prevents the from breaking. Asmall piece of freshly-cut metallic sodium is placed in the flask, and then asmall lot of water is added, i beg your pardon reacts through the sodium and causes it tobecome hot. The hot sodium climate reacts through the chlorine, producing abright yellow light, a great deal of heat energy, and also fumes of sodium chloride,which deposits on the wall surfaces of the bottle.
In the an initial video clip, the sodium flares up virtually immediately uponreaction v the water, and also "burns out" quickly. (Don"t blink,or you"ll miss it.) In the second, water is included twice, to develop oneshort flash, followed by a much much longer one. (This reaction can additionally be done with molten sodium, however I"ve never been braveenough to try that.)
Video Clip 1: REAL, 679 KB
!!! dangers !!!
Do not expose sodium metal to water! The reaction that sodium and also waterproduces hydrogen gas and also heat, i m sorry is no a good combination! Sodiummust it is in stored under mineral oil, or some other high-molecular weighthydrocarbon.
Chlorine gas is toxic, and extremely irritating to the eyes and also mucousmembranes.
This reaction evolves a an excellent deal of heat energy; make sure that the flaskhas no crack in it.
Bassam Z. Shakhashiri, chemistry Demonstrations: A Handbook for Teachers the Chemistry, Volume 1. Madison: The college of Wisconsin Press, 1983, p. 61-63.
Lee R. Summerlin, Christie L. Borgford, and also Julie B. Ealy, chemical Demonstrations: A Sourcebook because that Teachers, Volume 2, second ed. Washington, D.C.: American chemistry Society, 1988, p. 56-57.
man Emsley, The Elements, 3rd ed. Oxford, Clarendon Press, 1998, p. 56-57, 194-195.
David L. Heiserman, exploring Chemical Elements and their Compounds. Brand-new York: TAB Books, 1992, p. 43-48, 70-74.
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Martha Windholz (ed.), The Merck Index, 10th ed. Rahway: Merck & Co., Inc., 1983.