579 
of the reacting substances. One can substitute a nitro (NO,) group in 
a compound by the group (NH,) on warming it with a mixture of 
ammonium hydroxide and a ammonium salt and on the other hand, 
NH, is replaced by NO, when the salt is warmed with a nitrite solution. 
NH), (NH), 
2. C CI BOAC Cl, 
. [ee Cl | al 2 [eo uo) 
This hydrolysis reaction is catalytically accelerated by the presence 
of OH’ ions and the velocity is proportional to the concentration of 
hydroxide ions. 
(NH) (NH,) | 
Co ** | (OH),, | Co ~~ | OH! ete: 
[exo | [© wo, 
are strong bases and can be prepared in solution. The base obtained 
from the purpureo cobalt chloride is the aquopentammine hydroxide 
(NH,) 
C OH) 
| 0 H,O ( )s 
Chemical Laboratory, Muir Central College, Allahabad, India. 
