18 



OPTICAL ACTIVATION 



Table VI. 



g. d-acid and 0.0200 g. quinine in 11 ccm. acetoplienone. 

 (0.3305 mole acid and 0.0056 mole quinine per liter). 



Experiment 31. 



t; 



A — X 



fix _ X2 — Xi 



C - \ -"^1+^2 



.Ix 



(It 



% 



Experi- 

 ment. 







dt t, — Ij 



■-' 



-7^10- 

 Cm 







-160,0 











10 



151,6 



0,84 



155,8 



0,54 



5,3 



20 



138,4 



1,32 



145,0 



0,92 



13,5 



30 



124,9 



],35 



131,6 



1,02 



99 2 



40 



111,5 



1,34 



118,2 



1,13 



30^3 



50 



97,6 



1,39 



104,5 



1.33 



39,0 



60 



83,9 



1,37 



90,7 



1,50 



47,6 



70 



68,0 



1,59 



75,9 



2,08 



5 7,5 



80 



49,6 



1.84 



58.8 



3.13 



69,0 



90 



32,8 



1,68 



41.2 



4,08 



79,5 



100 



27,2 



0.56 



30,0 



1,87 



83,0 



110 



24.7 



0,25 



26,0 



0,96 



84,6 



140 



21.(3 



0,10 



23,2 



0.43 



86,5 



170 1 



19,1 



0,08 



20,4 



0,39 



88,1 



Here it i.s observed that the velocitv of the reaction increases 

 with .time, reaches a maxium, and then falls off rapidly to 

 nothing ; also that the ratio of the velocity of decomposition to 

 the mean concentration C,„ of the undecomposed acid behaves 

 in the same way. As should be expected, since quinine is a 

 laevo-rotatary substance, the rate of decomposition of the two 

 isomers is different. At the end of 70 minutes, when the 

 difference l^etween the percentage decomposition of the two 

 acids is greatest (almost 25 per cent), the veloci-ty of decom- 

 position of the 1- acid is almost double that of the d- acid. 

 The progress of the reaction with time is shown in fig. 2. 



