On account of the formation of an ammonium salt in the reaction.
The ammonium salt is most often employed, owing to the stimulant character of the ammonium base.
When some other source of nitrogen is present, such as asparagine or an ammonium salt, the amount falls to 005 to 01.
To the alcoholic solution, four times its volume of ether is added, when the ammonium salt is precipitated.
This is exactly what takes place when the base lime comes in contact with an ammonium salt, such as sulphate of ammonia.