In the preparation of sodium fusion extract,the purpose of fusing organic compound with a piece of sodium metal is to

In the Lassaigne's test,the Prussian blue precipitate is formed due to the formation of which compound?

Give the answers for the Lassaigne test:
$(i)$ If nitrogen and sulphur are both present,what observation is observed?
$(ii)$ If bromine is present,what is the observation?
$(iii)$ In the Lassaigne extract,if black precipitates are not obtained upon adding $CH_3COOH$ and lead acetate,what does this indicate?
$(iv)$ What is the reason for adding $FeSO_4$ to the Lassaigne extract?
$(v)$ Why is the Prussian blue colour observed?
$(vi)$ What does the violet colour with sodium nitroprusside in the Lassaigne extract indicate?

In the Lassaigne sodium fusion test,$N$ and $S$ of an organic compound are converted into:

Sodium extract is heated with concentrated $HNO_3$ before testing for halogens because

For testing halogens in an organic compound with $AgNO_{3}$ solution,sodium extract (Lassaigne's test) is acidified with dilute $HNO_{3}$. What will happen if a student acidifies the extract with dilute $H_{2}SO_{4}$ in place of dilute $HNO_{3}$?