In the quantitative estimation of sulfur in an organic compound,the amount of sulfur is determined in the form of which substance?

$6.46 \ g$ of $BaSO_4$ is obtained from $4.81 \ g$ of a compound in the estimation of sulphur by the Carius method. Calculate the percentage of sulphur in the compound. (Atomic masses: $Ba = 137, S = 32, O = 16$)

Discuss the Dumas method and its principles for the estimation of $N$ present in an organic compound.

In the Dumas method,$1 \ g$ of an organic compound gives $50 \ mL$ of $N_2$ gas at $300 \ K$ and $740 \ mm \ Hg$ pressure. If the aqueous tension at $300 \ K$ is $15 \ mm \ Hg$,what is the percentage of nitrogen in the compound?

When $0.15 \ g$ of an organic compound was analyzed using the Carius method for the estimation of bromine,$0.2397 \ g$ of $AgBr$ was obtained. The percentage of bromine in the organic compound is $.....$ (Nearest integer).
[Atomic mass: Silver $= 108$,Bromine $= 80$]

Calculate the percentage of nitrogen in $0.25 \ g$ of an organic compound if $38 \ cm^3$ of $N_2$ gas is evolved at $300 \ K$ and $96 \ kPa$ pressure. (Given: $1 \ atm = 101.3 \ kPa$)