276 Prtpartton of Acid in Salts, l^e. 



given quantity of a given neutral fait ; thus, how much deficcated foda will be requifite to 

 faturatc the acid contained in 50 parts cryftallized Epfom ? 



By the 4th table I fee that 100 parts real vitriolic acid are contained in 340 parts cryftal- 

 lized Epfom. Then if 340 : 100 : : 50 : I4)7, then by the 3d table I fee that 100 grains of 

 real vitriolic acid faturate 78,32 of foda. Confequently if 100 faturate 78,32 : : 14,7 would 

 faturate 11,51 of foda. 



Laflly, Irt the 6th table 1 find that 100 grains deficcated foda contain 60 of foda. Then 

 if 100 : 60 :: Jr: 11,51 ; then « = 19,1 parts deficcated foda. Then 19,1 parts deficcated 

 foda will faturate the acid contained in 50 parts cryftallized Epfom. 



Note ift. This problem is of ufe in determining the quantity of any precipitating fub- 

 flances to be employed in decompofitions, operated either by a fingle or double affinity. But 

 in moft cafes more of the precipitant muft be employed than the exa6t quantity neceflary for 

 faturation, and particularly when decompofitions are attempted in the dry way, as otherwife 

 a complete contadt with the fubftance to be decompofed will not be attained, or if volatile it 

 may be fublimed before the decompofition taices place. 



Prob. 12. Some analyfts have denoted the ftrength of their acids by expreffing the quan- 

 tities of each neceffary to faturate a certain quantity of alkaline liquor (and fometimes of 

 another bafis), without even telling whether the alkali was mild or cauftic, or the quantity 

 of it contained in the alkaline liquor. This problem is confequently indeterminate. How- 

 ever, a method of giving fome folutions of it may be underflood from the following example; 

 and circumftances will generally fliew whether the application to particular cafes be juft. 



Linktdh us that 240 grains of a vitriolic acid, which he employed, faturated 6,5 times 

 its weight of tartarin (he muft mean in a liquid ftate, as no vitriolic acid will faturate fix 

 times its weight of real alkali), and that 240 grains of the nitrous acid he employed faturated 

 2,5 times its weight of the fame alkali, ^ere, the fpec. gravity of both acids ? 



ift. It is plain, that fince 240 grs. of the nitrous acid faturated 2,5 times its weight of the 

 alkali, 624 grs. of that acid would faturate 6,^ times its weight of the alkali ; and firxe 624 

 grs. of the nitrous acid would faturate as much alkali a.s 240 of the vitriolic acid, then 260 grs. 

 of it would faturate as much alkali as 100 grs. of the vitriolic acid Could faturate. Ihere- 

 fore, fuppofing 100 of the vitriolic acid to contain 75 of real acid, fince more real nitrous 

 acid is required to faturate a given quantity of tartarin tiian of vitriolic acid, in the inverfe 

 ratio of 1214 to 1177 (as appears by the third table), then denoting the quantity of real 

 nitrous acid in 260 grs. of the nitrous liquor by x, we have the following equation, as 

 1214 : 1177 ::•*■: 75' and x = 77,55. Then 26ogrs.ofthe nitrous acid contain 77,55 of 

 real nitrous acid, confequently 100 grs. of it contained 29,82 real acid. And, therefore, its 



fp. grav. was nearly 1,234, and that of the vitriolic about 1,800. The quantity of 



alkali in the alkaline liquor might al(b on this fuppofition be determined. 



So if it be required to know how much common fait is requifite to decompofe a folution 

 cf nitrated filver containing 176,25 grs. of filver. 



ift. I find 



