NH_(2)NH_(2) contains nitrogen but still it does not give positive Lassaigne's test ? To get positive test for nitrogen in NH_(2)NH, what modification do you suggest ?

NH_(2)NH_(2) contains nitrogen but still it does not give positive Las

1.	NH_(2)NH_(2) contains nitrogen but still it does not give positive Lassaigne's test ? To get positive test for nitrogen in NH_(2)NH, what modification do you suggest ?
Answer» Solution :If hydrazine `(NH_(2)NH_(2))` is fused with Na metal, it does form NACN since it does not contain carbon and hence will not give +ve test for NITROGEN. In ORDER to test the presence of N in such compounds, during FUSION with Na, some charcoal or preferably starch (which contains C but N, S, halogens, etc.) is added. Under these conditions, C of starch or charcoal combines with N of the compound to form NaCN which will now give a +ve test for nitrogen.