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

In Lassaigne's extract of an organic compound,both nitrogen and sulphur are present,which gives blood red colour with $Fe^{3+}$ due to the formation of-

An organic compound containing phosphorus on oxidation with $Na_2O_2$ gives a compound '$X$'. This '$X$' when boiled with $HNO_3$ followed by treatment with ammonium molybdate reagent gives a yellow precipitate '$Y$'. '$X$' and '$Y$' respectively are:

The compound formed in the positive test for nitrogen with the Lassaigne solution of an organic compound is

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

Acidified sodium fusion extract on addition of ferric chloride solution gives blood red colouration,which confirms the presence of: