12 OPTICAL ACTIVATION 



tube of the cooler. Owing to the fact that carbondioxide 

 results from the oxidation of acetophenone, it was necessary 

 to remove every trace of oxygen from the nitrogen. Oxidation 

 of acetophenone was found to -take place with small traces of 

 oxygen at as low a temperature as 40. I assured .' myself that 

 the apparatus worked properly by means of a blank experi- 

 ment made every few days. This consisted in passing a current 

 of purified nitrogen through some solvent contained in the re- 

 action flask, and then through the soda-lime tubes. At the end of 

 1/2 1 hour the tubes were weighed and it was seen whether 

 they had increased in weight. 



The efficiency of the apparatus was tested by decomposing 

 a known weight of Na 2 CO, with pure dilute sulphuric acid, 

 and the evolved CO,, carried off with a current of dry pure 

 nitrogen into -the soda-lime tubes, after having been dried with 

 concentrated sulphuric acid. The results obtained were: 



0.3428 g. Na 2 CO s liberated 0.1419 g. CO*; calculated 

 0.1423 g. Error: -0.3%. 



As a further test of the efficiency of the apparatus the 

 velocity constant of decomposition of d- and 1- camphor- 

 carboxylic acids was measured. As Fajans has found, the 

 reaction follows the first order. /; has been calculated from 

 the formula : 



k _1 ](r A 



f 0,4343 g A^' 



\vhere t is the time in minutes, A the original amount of acid 

 calculated as CO 2 and A x the amount present at the time 

 t, both expressed in milligrams. 



