In Dumas method for the estimation of $N_2$,the sample is heated with copper oxide and the gas evolved is passed over :

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: $1 \ atm = 101.3 \ kPa$)

In Carius method of estimation of halogens,$250 \ mg$ of an organic compound gave $141 \ mg$ of $AgBr$. The percentage of bromine in the compound is:

$A$ sample of $0.50 \, g$ of an organic compound was treated according to Kjeldahl's method. The ammonia evolved was absorbed in $50 \, mL$ of $0.5 \, M \, H_{2}SO_{4}$. The residual acid required $60 \, mL$ of $0.5 \, M \, NaOH$ solution for neutralisation. Find the percentage composition of nitrogen in the compound. (in $\%$)

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

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 $Hg$ ]