Action of some Alkaline Salts upon Sulphate of Lead. 83 



composed by continued contact with water, or still more rapidly 

 by its solution being boiled. 



Acetate of ammonia. — This salt also dissolves to some extent 

 the sulphate of lead, but not so readily as either of the above 

 salts. If the solution be boiled and evaporated to dryness, crys- 

 tals of sulphate of ammonia are obtained, and an uncrystallizable 

 salt of lead, probably an acetate of lead and ammonia ; from the 

 difficulty of separating the sulphate of ammonia from it, it is im- 

 possible to pronounce positively whether it is a double salt, or 

 simply an acetate of lead. We see in this reaction the existence 

 of a soluble salt of lead and the sulphate of ammonia simultane- 

 ously in the same solution, without a precipitate being formed. 



Oxalate of ammonia. — Dissolves but slightly the sulphate of 

 lead, owing no doubt to the impossibility of forming a double 

 salt ; but it will nevertheless decompose largely, the sulphate 

 furnishing the oxalate of lead. 



Bluriate of ammonia, if boiled with the sulphate of lead will 

 decompose it instantaneously, furnishing the chloride of lead and 

 sulphate of ammonia. 



The nitrate of ammonia does the same, forming nitrate of lead 

 and sulphate of ammonia. 



The carbonate and succinate of ammonia produce similar, ef- 

 fects. 



The action of most of the corresponding salts of potash and 

 s'bda was examined, and with very similar results. The fact is, 

 it would appear that those alkaline salts which dissolve the sul- 

 phate of lead, decompose it, without reference to the time oc- 

 cupied in the solution, as in the case of the carbonate of ammo- 

 nia, which decomposes the sulphate at the very instant of its so- 

 lution ; and it is impossible to detect at any one time other than 

 a trace of lead in solution, whereas the quantity of sulphuric acid 

 is constantly increasing. 



The explanation is clear : the sulphate of lead is a salt with a 

 strong acid and feeble base ; the alkaline salts used, contain 

 feebler acids and stronger bases ; they dissolve the sulphate, thus 

 affording an opportunity for the acids and bases to act upon one 

 another, under favorable circumstances, and to follow a natu- 

 ral law in chemistry, the stronger acid combined with the stronger 

 bases, and vice versa. 



