An organic compound having molecular mass 60 is found to contain $\mathrm{C}=20 \%, \mathrm{H}=$ $6.67 \%$ and $\mathrm{N}=46.67 \%$ while rest is oxygen. On heating it gives $\mathrm{NH}_3$ alongwith a solid residue. The solid residue give violet colour with alkaline copper sulphate solution. The compound is