Solubility of Salts in Water. 385 



1. Solutions containing KC1 and NaCl. 



The saturated solution, when both salts are added in excess 

 to water, was found to contain 44*70 parts of mixed salts to 

 100 parts of water. If this be the true solubility of the salts, 

 and the formulae given on p. 383 be correct, then 



44-70 = 34-52 + n 0*5707 +n 2 0-0545 



and 44*70 = 35*91 + n2'603, 



the former equation giving the molecules of NaCl, the latter 

 those of KC1 present in the saturated solution. 

 The equations worked out give 



9-394 molecules NaCl per 100 H 2 



3-777 molecules KC1 per 100 H 2 0, 



and 



or 



and 



or 



30-54 parts of NaCl per 100 of water 

 13-99 parts of KC1 per 100 of water, 



44*53 parts of mixed salts per 100 of water ; 



an error of — 0*17 part per 100 of water, showing the 

 correctness of both the formulae and the direct determination. 

 From the above calculation we find that the 44*7 parts of 

 mixed salts contain 14*075 parts of KC1 and 30*625 parts of 

 NaCl; or, in molecules per 100 H 2 0, 3*396 KC1 and 9*423 

 NaCl ; or, 1 part of KC1 to 2*176 parts of NaCl and 1 mole- 

 cule KC1 to 2*775 molecules NaCl. 



2. Solutions containing KC1 and KN0 3 . 



The saturated solution formed when both salts are added in 

 excess to water was found to contain 51*87 parts of mixed 

 salts to 100 parts of water. If this be the true solubility, and 

 the formulae be correct, then 



51*87 = 34*52 + 7i5*26, 



51*87 = 31*11 + n 0*959 + n 2 0*261 -n 3 0*0065 ; 

 the former equation giving the molecules of KN0 3 , the latter 

 those of KC1 present in the saturated solution. 

 The equations worked out give 



3*298 molecules KN0 3 per 100 H 2 



and 7*925 molecules KC1 per 100 H 2 0, 



or 



18*95 parts of KN0 3 per 100 of water 



32-84 parts of KC1 per 100 of water ; 

 Phil. Mag. S. 5. Vol. 31. No. 192, May 1891. 2 F 



