386 Mutual Solubility of Salts in Water. 



an error of —0*08 part per 100 of water. The formulae and 

 the direct determination are therefore correct. 



3. Solutions containing NaCl and NaN0 3 . 



The saturated solution formed when both salts were added 

 in excess to water was found to contain 78 89 parts of mixed 

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

 the formulae be correct, then 



78-89 = 87-64-n 2-378 + n 2 0'263 -n z 0*01325, 

 78-89 = 35-91 + ^3-722. 



The former equation gives the molecules of NaCl, the latter 

 those of NaN0 3 present in the saturated solution. 

 The equations worked out give 



and 



or 



and 



7-662 molecules NaCl per 100 H 2 

 11-55 molecules NaN0 3 per 100 H 2 0, 

 24-91 parts of NaCl per 100 of water 

 54-55 parts of NaN0 3 per 100 of water 



an error of + 0'57 part per 100 of water. The formulae and 

 the direct determination therefore very fairly agree. 



4. Solutions containing NaN0 3 and KN0 3 . 



The saturated solution formed when both salts are added in 

 excess to water was found to contain 134*21 parts of mixed 

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

 then 



134-21 =87-64 + ^6-65, 



134-21 = 31-ll + n4-429+7i 2 0'0663-n 3 0-00153. 



The former equation gives the molecules of KN0 3 , the latter 

 those of NaN0 3 present in the saturated solution. 

 The equations worked out give 



7-005 molecules KN0 3 per 100 H 2 



and 20-039 molecules NaN0 3 per 100 H 2 0, 



or 



39-34 parts of KN0 3 per 100 of water 



94-60 parts of NaN0 3 per 100 of water; 



an error of —0*27 part per 100 of water. The formulae and 

 the direct determination therefore agree. 



The mutual solubility of potassium and sodium nitrates 

 has been specially studied by Carnelley and Thomson, whose 



