FUNDAMENTAL CONCEPTIONS 203 



H 



Formic acid, 0=C^ 169 



OH 



H 



Formhydroxamic acid, 0=C^ 85 



NHOH 

 H 



Formylchloride, 0=C^ below 20 



Cl 



Since these substances containing quadrivalent carbon decom- 

 pose spontaneously into carbon monoxide, i. e., cannot exist in the 

 quadrivalent condition at temperatures above those indicated, it is 

 self-evident that at lower temperatures the addition products must 

 be partially dissociated and that in the future we must be able to 

 determine in each case with absolute accuracy the per cent of dis- 

 sociation at any temperature. A striking experiment with formhy- 

 droxamic acid, dissociation-point 85, proves the correctness of this 

 conclusion; on allowing this crystalline substance to stand at 20 in 

 acetone solution the following reaction takes place quantitatively: 



HONH 



H 



HO 



NOK + H-OH+ ^C: O-^(CH 3 ) 2 : C=NOH+ ^C: 0. 



H 



In a similar manner we can prove that the isonitrile addition pro- 

 ducts, many of which have definite boiling-points and are quite stable, 

 are partially dissociated at ordinary temperatures. Thus the addition 



X 



products with halogen RN=C^ are all converted back quantita- 



X 



tively into the alkylisocyanides by treatment with finely divided 

 metals, zinc-dust or sodium, which simply abstract the free halogen. 

 Many of the acylhalide addition products dissociate spontaneously 

 into the components on distillation; these phenomena are perfectly 

 analogous to the dissociation of dry ammonium chloride : 



