Action of some Alkaline Salts upon Sulphate of Lead. 81 



Art. Y. — Action of some of the Alkalijie Salts upon the Sulphate 

 of Lead ; by J. Lawrence Smith, M. D. 



It has been for some time known, that certain neutral salts 

 possess the property of dissolving to some extent the sulphate of 

 lead, which property belongs neither to the acids or bases consti- 

 tuting these salts. By referring to Berzelius' Chemistry, it will 

 be found that the acetate and nitrate of ammonia are among the 

 number. " 1 part of the sulphate was dissolved in 47 parts of a 

 solution of the acetate, of sp. gr. 1-036; and in 172 parts of a 

 solution of the nitrate, of sp. gr. 1-144." In the Annalen der 

 Chem. und Phar. Vol. xxxiv, 23.5, will be found the following 

 statement under the head of Reactionen: "Sulphate of lead is 

 easily dissolved, and in a large quantity, by a solution of neutral 

 tartrate of ammonia. A concentrated solution forms after some 

 time a stiff jelly, like silica." This last is no doubt a double tar- 

 trate of lead and ammonia. 



I had also observed some time previously, that a solution of 

 the citrate of ammonia, when poured upon the sulphate of lead 

 and allowed to stand, altered the character of the sulphate, and 

 this, with the other fact above stated, led to the examination of 

 what was really the action of these as well as other ammoniacal 

 salts in general, upon the sulphate in question, and it was found 

 that in every case it was decomposed. 



Citrate of ammonia. — If a solution of citrate of ammonia be 

 poured upon the sulphate of lead and shaken together, the clear 

 solution will be found to contain the sulphate of lead, as shown 

 by hydrosulphuric acid, and a salt of baryta — (taking care in 

 testing with the baryta to acidulate first with pure nitric acid, to 

 prevent the formation of the citrate of baryta.) If they be al- 

 lowed to remain several weeks in contact, the solution will be 

 found to contain more lead, the sulphate having undergone de- 

 composition, sulphate of ammonia and a double citrate being the 

 result ; as this latter salt is not very soluble, a large portion of it 

 remains in the form of a precipitate. The rapidity of this change 

 is in proportion to the concentration of the solution of the citrate. 

 If instead of performing the experiment in the cold, we boil a tol- 

 erably concentrated solution of the citrate with the sulphate of 

 lead, a very large quantity of the latter will be dissolved, and the 



Vol, XLVii, No. 1.— April-June, 1844. 11 



