78 



Conductivities and Viscosities in Pure and in Mixed Solvents. 



In order to ascertain if this same decrease in the transmissions, cor- 

 responding to an increase in the red component, would take place on 

 standing with solutions of indicators which are incompletely trans- 

 formed, the following series of solutions were prepared : 



SOLUTIONS. 



No. 1. 50 c.c. rosolic acid; 25 c.c. Na 2 HPO 4 ; 



No. 2. 50 c.c. rosolic acid; 25 c.c. Na 2 HPO 4 ; 



No. 3. 50 c.c. rosolic acid; 25 c.c. Na 2 HPO 4 ; 



No. 4. 50 c.c. rosolic acid; 25 c.c. Na2HOP4; 



TABLE 49. 

 [(I /Io) depth of solution = 20 mm.] 



1 c.c. HC1 diluted to 100 c.c. 



5 c.c. HC1 diluted to 100 c.c. 

 10 c.c. HC1 diluted to 100 c.c. 

 15 c.c. HC1 diluted to 100 c.c. 



In table 49 are given the percentage transmissions for a depth equal 

 to 20 mm. of the above series of solutions. The transmissions were 

 determined after the solutions had stood for intervals of 5, 16, and 24 

 hours. The transmission values recorded in columns 1 and 3 were 

 determined with the same series of solutions. A new series of solutions 

 was prepared for the 16-hour determination, the results of which are 

 recorded in column 2. Solution No. 1 was not made up for this deter- 

 mination. Duplicate measurements are given in every case. 



An examination of the transmission values recorded for solutions 1 

 and 2, table 49, shows that a decrease in the transmissions of incom- 

 pletely transformed solutions of rosolic acid also takes place on standing. 

 Solution 2, in which the hydrogen ion concentration is 4.484 X1CT 8 , 

 has come to equilibrium between 5 and 16 hours, as is shown by the fact 

 that the transmission values become constant after 16 hours. In 

 solutions 3 and 4, in which the hydrogen ion concentrations are respec- 

 tively 10.53XKT 8 and 19.52 Xl(T 8 , equilibrium was established before 

 standing 5 hours. This points to the conclusion that in the incom- 

 pletely transformed solutions of the indicator the more alkaline the 

 solution the greater the time before equilibrium is established. 



