( ^'^4 ) 



the properties of isonitrosoacetophenon : CgH/JOCH : NOH. This sub- 

 stance appeared to l)e a fiiirly strong acid. The sodium salt suffers 

 a remarkable decompositiou into sodium benzoate and hydrogen 

 cyanide when touched with a hot substance, when moistened with 

 a drop of strong acid or when warmed with ecess of aqueous soda. 



C«H,C01CH : N|ONa = CoH^COUXa + CNH. 



The HCN-molecule is therefore, so to speak removed from the 

 molecule of the sodium salt whilst ONa migrates to the carbonylgroup. 

 Ci.AisEN further states that after being heated for two days with two 

 mols. of ?z-soda, the sodium salt had been completely converted into 

 sodium cyanide and benzoate. 



It was of importance to subject this reaction to a further dyna- 

 mical research to determine its order and to investigate the influence 

 of the addition of alkali and of a salt and also that of the solvent. 



The sodium salt was made according to Claiskn'.s directions. As 

 a perfectly pure salt was required, it was prepared by recrystallising 

 the free isonitrosoderivative from chloroform and neutralising this 

 with the equivalent quantity of sodium alcoholate. 



If the salt is dissolved in 70 % alcohol, it may be precipitated 

 by addition of ether as a ^-ellowish coloured hydrate containing four 

 mols. of water of crystallisation. 



Found: 29.5% H,0, calcul. : 29.6"/;,. The salt obtained on drying 

 contained 13.5 "/q of sodium, theory 13.45 "/o- When gently heated 

 the yellow salt loses water and turns orange-red, which is the colour 

 of the anhydrous salt. 



After some fruitless efforts to trace the progress of the transformation 

 by titration it was found that this may be accurately done by 

 the aid of the colorimeter, for the aqueous solution of the sodium 

 salt is yellow whilst the decomposition products are colourless. 



In the preliminary experiments required for ascertaining the pro- 

 porties of the colorimetric standard liquid, it was found that the 

 colour of the dissolved salt is modified by dilution. The concentrated 

 solutions of the sodium salt have an orange tinge, which turns 

 yellow on dilution; the experiment fui'thei' s!i()\v<m1 thai, ifwc work 

 with solutions not exceeding I "/„, the diminution in colom- may be 

 taken as proportionate to the dilution. This docs not hold good for 

 more concentrated solutions ; 100 c.c. of a 1 " „ solution is colori- 

 metrically equal to 47 c.c. of a 2 "/^ solution and not to 50 c.c. 



These phenomena are probably connected with the increasing- 

 electrolytic dissociation of the salt on dilution. As the acpieous 

 solution has an alkaline reaction, a perceptible hydrolytic decompo- 



