Which method uses an instrument called a nitrometer?

In Duma's method of estimation of nitrogen,$0.1840 \, g$ of an organic compound gave $30 \, mL$ of nitrogen collected at $287 \, K$ and $758 \, mm$ of $Hg$ pressure. The percentage composition of nitrogen in the compound is $......$ . (Round off to the Nearest Integer). [Given : Aqueous tension at $287 \, K = 14 \, mm$ of $Hg$ ]

$A$ student has been given $0.314 \ g$ of an organic compound and asked to estimate Sulphur. During the experiment, the student has obtained $0.4813 \ g$ of barium sulphate. The percentage of sulphur present in the compound is . . . . . .
(Given Molar mass in $g \ mol^{-1}$: $S = 32$, $BaSO_4 = 233$) (in $\%$)

$0.8 \ g$ of an organic compound was analysed by Kjeldahl's method for the estimation of nitrogen. If the percentage of nitrogen in the compound was found to be $42 \ \%$,then $.... \ mL$ of $1 \ M$ $H_2SO_4$ would have been neutralized by the ammonia evolved during the analysis.

In the estimation of sulphur in an organic compound,upon treatment with concentrated $HNO_3$,it is converted into:

What are the formulas,names,and molecular masses of the compounds obtained during the estimation of phosphorus in organic compounds?