The salt K2S03 H20 may be obtained by crystallizing the metabisulphite, K 2 S 2 0 5 (from sulphur dioxide and a hot saturated solution of the carbonate, or from sulphur dioxide and a mixture of milk of lime and potassium sulphate) with an equivalent amount of potash.
In the case of the Clark standard cell above mentioned the elements are mercury and zinc separated by a paste of mercurous sulphate mixed with a saturated solution of zinc sulphate.
A saturated solution is a system in equilibrium, and exhibits the thermodynamic relations which hold for all such systems. Just as two electrified bodies are in equilibrium when their electric potentials are equal, so two parts of a chemical and physical system are in equilibrium when there is equality between the chemical potentials of each component present in the two parts.
A saturated solution of potassium chlorate in strong nitric acid is added, and the mass evaporated to dryness.
Arsenic can also be estimated by volumetric methods; for this purpose it must be in the arsenious condition, and the method of estimation consists in converting it into the arsenic condition by means of a standard solution of iodine, in the presence of a cold saturated solution of sodium bicarbonate.
The heptahydrate, Na2C03.7H20, is obtained by crystallizing a warm saturated solution in a vacuum; it appears to be dimorphous.
Hydroferricyanic acid, H 3 Fe(NC)s, obtained by adding concentrated hydrochloric acid to a cold saturated solution of potassium ferricyanide, crystallizes in brown needles, and is easily decomposed.
To do this, saturated ammoniacal liquor is decomposed by lime in the presence of steam, and the freed ammonia is passed into strong sulphuric acid, the saturated solution of ammonium sulphate being carefully crystallized.
According to Michel and Kraft, one litre of cold saturated solution of tin crystals weighs 1827 grammes and contains 1333 grammes of SnCl 2.
Or, by increasing the pressure, we eliminate the vapour and obtain the curve OF giving the relation between pressure, freezing point and composition when a saturated solution is in contact with ice and salt.