DILUTION OF CONCENTRATED SOLUTIONS. 

 The following table shows the good agreement obtained : 



347 



THOMSEN does not quote an expression for this acid. It is seen as before that the 

 above type of equation gives good agreement over those ranges in which heat is most 

 generated, and therefore most accurately measured. As with nitric acid, no limiting 

 hydrate appears to be formed since 



dQ _ 3356 



cZN '' N 



The graph for this relation is shown in Diagram II. 



(4) Acetic Acid. 



This solution differs from all the others since the heat of dilution for the highest 

 concentrations is negative, acquires a minimum value, rises to zero and for dilute 

 solutions becomes positive. 



The results do not lend themselves to either of the forms of equation used by 

 THOMSEN. Results are quoted for concentrations between CH 3 . COOH . ^H,O and 

 CH 3 . COOH . 8H 2 0. The greatest measurable thermal changes occur in this range. 



An equation is developed by the method of least squares, and found to be 



Q = -63'49 log e N + 40'84 N-194'09, 



and the table here given shows the order of agreement between experimental results 

 and those calculated. 



