Experiments with alkali metals or their compounds

 

  element required compound link to experiment
*

Cs

KBrO3

S8

any soluble Cs-salt

Beautiful blue light with cesium bromate . Cesium bromate is made, and a mix of this with sulphur is burned, giving a beautiful blue flame color.

*

K

KOH

Mg (coarse powder)

tert-butanol

Aliphatic solvent, boiling around 220 C, free of aromatics

Synthesis of potassium from magnesium and potassium hydroxide . This is an interesting and also remarkable synthesis of potassium, which can be carried out at very mild conditions and which only requires reactants which are not really hard to obtain.

*

K

Cs

KCl

CsCl (optional)

K2Cr2O7 (optional)

HCl (dilute, optional)

Tutorial for making a miniature electrolysis cell for chlorate production. This is not really an experiment, it is a description of how one can setup a nice small electrolysis cell, suitable for making chlorates from chlorides. The good working of this cell is demonstrated for making potassium chlorate and cesium chlorate.

*

K

KIO3

HCl (30%)

CH3COCH3

H2SO4

H2O2 (3%)

Na2SO3

Preparation of polyhalide salt of potassium. Potassium iodate is added to concentrated hydrochloric acid. Chlorine gas is formed, and needle-like crystals of potassium tetrachloroiodate(III) are formed as well. This is a remarkable polyhalide compound.

 

Li

LiCl (or LiBr)

Colored flames with metal salts. Metals salts are mixed/dissolved in ethanol, soaked in paper and ignited, one of the salts being lithium bromide.

 

Na

phenolphtalein pH indicator

Sodium skirting over water surface. This is a very simple experiment. Some sodium is thrown in a tank, filled with water, in which some pH indicator is dissolved. This results in a nice visual effect.

 

Na

Na

HCl (dilute)

Dangerous experiments with sodium metal. Sodium metal is put in dilute hydrochloric acid. The heat, produced in this reaction, ignites the hydrogen, also formed in this reaction. This leads to a loud bang!

*

Rb

Rb2CO3

HIO3

HCl (30%)

A polyhalide compound of rubidium. Rubidium is known to form polyhalide compounds fairly easily, more so than the lighter alkali metals. In this experiment such a compound is prepared. During the preparation a beautiful crystalline precipitate is formed.

* Cs, Cu, Co, Fe

CuCl22H2O

CsCl

HCl (30%)

 

CoCl26H2O (optional)

FeCl36H2O (optional)

Red complex of copper and chloride. A really beautiful and remarkable solid chloro complex of copper is produced. The complex has copper in oxidation state +2 and has a bright red color, which is very special for copper in oxidation state +2. A few other similar complexes of other metals are described as well through this webpage. All these complexes depend on the special solubility properties of their cesium-salt.

 

 

   

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