What happens to the halogen when $AgNO_3$ is added to the Lassaigne solution acidified with $HNO_3$?

The volume of nitrogen is measured by which apparatus in the Dumas method?

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

If on adding $FeCl_3$ solution to acidified Lassaigne solution of an organic compound a blood red colouration is produced,it indicates the presence of

What happens when an organic compound is fused with sodium metal?

Three students,Manish,Ramesh,and Rajni were determining the extra elements present in an organic compound given by their teacher. They prepared the Lassaigne's extract $(L.E.)$ independently by the fusion of the compound with sodium metal. Then they added solid $FeSO_4$ and dilute sulphuric acid to a part of the Lassaigne's extract. Manish and Rajni obtained prussian blue colour,but Ramesh got red colour.
Ramesh repeated the test with the same Lassaigne's extract,but again got red colour only. They were surprised and went to their teacher and told him about their observation. Teacher asked them to think over the reason for this. Can you help them by giving the reason for this observation? Also,write the chemical equations to explain the formation of compounds of different colours.