DECOMPOSITION PRODUCTS 



22 



late and that required for the different fractions. If, for 

 example, the total amount of lime-water =a, and if for the 3rd 

 fraction the number b had been read off on the burette, then : 





. b. 



The series of numbers obtained in this way are as follows : 



TABLE B. 



It is easy to decide which of the acids is being dealt with 

 by comparing the numbers which are obtained with those in 

 Table B. Further, if a series of numbers corresponding to those 

 given in Table B for acetic acid were obtained, then the amount 

 of this acid in the original 110 c.c. can be got by looking 

 up the factor corresponding to 100 c.c. (the volume distilled 

 over). This factor is 80 (Table A), so it is only necessary to 



multiply the amount of acid found in 100 c.c. by =- to get 



O v/ Tfl 



the whole of the original quantity. 



Where a mixture of two acids has to be dealt with, the con- 

 ditions are somewhat more complicated, but both the acids 

 can be estimated quantitatively if they have been determined 

 qualitatively, as in Orla Jensen's method. It has already been 

 mentioned that each acid on distillation behaves as though it 

 alone were present. If, therefore, a mixture of equivalent 

 quantities of two acids is present, the figures obtained by the 

 method described above are the arithmetical mean of the series 

 of numbers given by the two acids in question. The curve 



