1075 



Conversely the solution d' obtained will again have to take up 

 0,465 gTm.mols. of KCl and NaNO^ and deposit the same quantity 

 of XaCl in order to pass into 1 gram. mol. i^ (J 00). In this method 

 of working 0,465 grm.mol. of salpetre are converted per grm.mol. 

 P, 100° (122,2 grams) that is 0,380 grm. mols. per 100 grams of 

 solution. 



If we compare the yields of these four processes, it appears that, 

 in the continuous process, the transformation per 100 grams of 

 solutions at J 00° amounts to 



0,345 grammolecules in the method of working I 



\J,2iX)i ,, ,, ,, ,, ,, ,, II 



• 0,461 ,, „ „ „ „ „ III 



0,380 „ „ „ „ „ „ IV 



Hence, III and IV give the largest transformation. 



This is in agreement with the practical experience in the con- 

 version. 0. Dammer \) states about this, that, nowadays one does 

 not add together KCl and NaNO^ in exactly equivalent quantities 

 but uses an excess of NaNO, so as to ensure a complete decomposi- 

 tion of the KCl. 



We further notice that in all four processes, after heating at 100° 

 and removing the NaCl, an addition of water is necessary to prevent 

 simultaneous separation of NaCl with the KNOj. In practice, this 

 seems not to be done. The crude potash salpetre will, therefore, 

 contain NaCl-crystals which are removed by v/aslting with cold 

 water. 



Finally, I tender my sincere thanks to Miss J. Ph. van Rees and 

 Mr. R. DE Lange for their assistance and the care with which they 

 have executed the analyses. 



Laboratory for anorganic and physical chemistry 

 of the Technical High School. 



Delft, January 1914. 



') Handbuch der chemitclien Teclmologic. I. 8i>7 (I'.l'Jo). 



