66 



Conductivities and Viscosities in Pure and in Mixed Solvents. 



were again made with solution II, 15 minutes later. The results are 

 recorded under III. By comparing the transmission values, the effect 

 of the bleaching for an interval of 15 minutes can be noted. Solution 

 IV contained 0.5 c.c. alkali, and was kept in the dark nearly a half-hour 

 before being used. Solution V, containing 1 c.c. of alkali, was used 

 about 4 hours after being prepared. 



Similar experiments were made with solutions of phenolphthalein, 

 partially converted into the quinoid salt, and it was found that such 

 solutions are fairly stable. Very little change in transparency could be 

 detected during the first 4 or 5 hours after the solutions were prepared. 



TABLE 38. 

 [I/I for depth of solution =20 mm.] 



RESULTS WITH PHENOLPHTHALEIN. 



The six solutions recorded below were prepared from the following 

 mother solutions. The concentration of the phenolphthalein was 

 6.697 X 10~ 5 gram-molecules per liter; that of the ammonium hydroxide 

 0.1448 gram-molecules per liter, and that of the ammonium chloride 

 0.1 gram-molecules per liter. 



SOLUTIONS. 



I. 75 c.c. phenolphthalein, diluted to 100 c.c. 

 II. 75 c.c. phenolphthalein, 2 c.c. NH 4 OH, 1 c.c. NH 4 C1, diluted to 100 c.c. 



III. 75 c.c. phenolphthalein, 2 c.c. NH 4 OH, 2 c.c. NH 4 C1, diluted to 100 c.c. 



IV. 75 c.c. phenolphthalein, 2 c.c. NH,OH, 5 c.c. NH 4 C1, diluted to 100 c.c. 

 V. 75 c.c. phenolphthalein, 2 c.c. NH 4 OH, 10 c.c. NH 4 C1, diluted to 100 c.c. 



VI. 75 c.c. phenolphthalein, 1 c.c. N NaOH, diluted to 100 c.c. 



TABLE 39. 



[I/Io for depth of solution =20 mm. Temperature = 20.] 



