Question

In the Lassaignes test the Sulphur present in
the organic compound first changes into:

• A. $N{a}_{2}S{O}_3$
• B. $C{S}_2$
• C. $N{a}_{2}S{O}_4$
• D. $N{a}_{2}S$

Answer 1

Answer: (D)

$N{a}_{2}S$

The elements in the organic compound react with sodium during fusion reaction as follows:
Na + C + N ------------> NaCN (if N is present)
2Na + S ----------------> Na2S (if S is present)
Na + S + C + N --------> NaSCN (if both N & S are present & insufficient amount of Na is used)
Na + X -------------------> NaX (If halogens are present)
Where
X = Cl/Br/I
Hence SFE may contain any of or all of the ionic forms of respective elements.