Question

Consider the following sequence
$Na\left(extract\right)+FeS{O}_4\stackrel{NaOH}{\to }\left(A\right)\underset{H_{2}S{O}_4}{\overset{Dil.HCl}{\to }}Greencolour$
Freshly prepared solution Solution (Filtrate)
The presence of green colour confirm the presence of:

• A. $N$
• B. $S$
• C. $O$
• D. $N$ and $S$ both

Answer 1

The correct option is A $N$

The presence of green colour confirm the presence of $N$. Nitrogen present in the compound, the Lassaigne's extract would contain sodium cyanide formed during fusion. Sodium cyanide is converted to sodium ferrocyanide giving green colour on treating with ferrous sulphate.