Sodium

Sodium, Na, is a Alkali Metal element, found in Group Ia of the periodic table.

Atomic Number : 11
Atomic Mass : 22.9898

Discovery

Sodium metal was first isolated by Sir Humphery Davy in 1807AD by the electrolysis of fused caustic soda.

Occurrence

Sodium is an abundant metallic element which is widely distributed. However, because of its high reactivity is not found naturally in its elemental state.

Sodium Chloride is present at a concentration of 3.5% in seawater.

Extraction

Sodium metal is isolated by the electrolysis of fused caustic soda.

Preparation

Manufacture

Sodium metal is manufactured using the Castner Process, where fused caustic soda which is mixed with a little carbon and iron is subjected to electrolysis at 1000 degC.


	6 NaOH   +   C   ==>   2 Na   +   3 H2   +   2 Na2CO3

Properties

Sodium metal is a soft silvery-white lustrous metal which can be easily cut with a knife.

Sodium metal is highly reactive and tarnished readily in air due to the formation of a layer of Sodium Oxide on the surface of the metal.


		4 Na   +   O2   ==>   2 Na2O

Reactions

Sodium is highly reactive chemically, and must be stored under liquid Paraffin, which contains no Oxygen, to prevent oxidation.

Sodium burns readily in air forming a mixture of sodium oxide and sodium peroxide.


	   4 Na   +   O2   ==>   2 Na2O   	
	   2 Na   +   O2   ==>   Na2O2

Sodium reacts readily with the halogens, forming the appropriate sodium salt.


	   2 Na   +   Cl2   ==>   2 NaCl

Sodium reacts violently with water forming sodium hydroxide and liberating hydrogen. The heat evolved inn the reaction is sufficient to ignite the hydrogen that is liberated.
2 Na + 2 H2O ==> 2 NaOH + H2

Sodium dissolved in liquid ammonia forming sodamide.


	   2 Na   +   2 NH3   ==>   2 NaNH2   +   H2

Uses
Sodium is used

in the manufacture of sodium peroxide, sodium cyanide and sodamide,
as a reagent in organic chemistry as a powerful reducing agent, and
as a coolant in some nuclear reactors.

Detection and Analysis
Sodium is detected in its compounds by the bright yellow colouration which it imparts to flames when burned and by spectroscopic methods.

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