Give the chemistry of Lassaigne's test for detection of` N` in an organic compound.

Explanation

If nitrogen and sulphur both are present in an organic compound, they form sodium thiocyanate (sodium sulphocyanide) when fused with sodium. Then the compound formed reacts with ferric chloride to form ferric thiocyanate. Blood red colouration appears due to ferric thiocyanate. This blood red colouration indicates the presence of nitrogen and sulphur in an organic compound.
`Na + C + S + N overset(Delta)(rarr)underset("Sodium thiocytante")(NaSCN)`
`Fe^(+3) + 3NaSCN + underset("(Blood red colouration)")underset("Feric thiocyanale")(Fe(SCN)_3 + 3Na^(+))`