1903-4.] Physico-Chemical Investigations in Amide Group. 53 
and in the case of acetamid as ‘111. The calculated and observed 
values agree well with one another. There is no indication of 
any negative viscosity in the case of carbamide. As the substance 
employed was very pure, I have some difficulty in explaining the 
different result obtained by Rudorf. In case the solution used by 
him had undergone any decomposition (into ammonium cyanate), 
I heated some \ mol. solution of urea for an hour at 100° C. to 
see whether the production of ammonium cyanate would affbct the 
result : the solution had a viscosity almost identical with the 
result previously obtained for pure urea, an increase of '002 being 
found. 
The Chemical Nature of the Amides. 
The amides are above described as non-electrolytes, but I 
thought it might be of interest to inquire as to how far this was 
the case, and to what the amides owe such conductivity as they do 
possess. In the following measurements I have used urea as the 
amide. 
The amides are known to form compounds with acids. Thus 
urea and hydrochloric acid give the compound C0(NH 2 ) 2 ,HC1. 
These compounds are split up very largely into amide and acid 
again by dissolving in water. 
Walker showed* that the concentration of free acid in a solu- 
tion is gradually decreased by the addition of urea, and the 
relations here may be represented by the formula 
Cco(nh 2 ) 2 X Chci 
Cco(nh 2 ) 2 ,hci 
where C x is the concentration of the 
constant. 
substance x and K is a 
He found that if the concentration 
of H' ions in normal 
hydrochloric acid be represented by the number 315 (25° C.), then 
the concentration after addition of urea was as follows : — 
Norm. HC1 
. 315 
„ +1 mol. CO(NH 2 ) 2 
. 237 
jj + 1 j? j> 
. 184 
55 5 5 5’ 
. 114 
55 + 3 ,, ,, 
. 82 
55 ^ 5 5 5 5 
. 60 
* Zeit. fur physical. Chemie , 4, 319 (1889) 
