In the $Dumas$ method,the nitrogen-containing organic compound is first heated with which of the following?

In Dumas method for estimation of nitrogen,$0.3 \ g$ of an organic compound gave $41.9 \ mL$ of nitrogen gas at $\text{STP}$. What is the percentage of nitrogen (in $.5$)?

$0.2 \ g$ of an organic compound was subjected to estimation of nitrogen by Dumas method in which volume of $N_2$ evolved (at $STP$) was found to be $22.400 \ mL$. The percentage of nitrogen in the compound is $.......$. [nearest integer] (Given: Molar mass of $N_2$ is $28 \ g \ mol^{-1}$. Molar volume of $N_2$ at $STP$ : $22.4 \ L \ mol^{-1}$ )

When $1 \ g$ of compound $(X)$ is subjected to Kjeldahl's method for the estimation of nitrogen, $15 \ mL$ of $1 \ M$ $H_2SO_4$ was neutralized by the ammonia evolved. The percentage of nitrogen in compound $(X)$ is:

$1.2 \ g$ of an organic compound on Kjeldahlization liberates ammonia which consumes $30 \ cm^3$ of $1 \ N \ HCl$. The percentage of nitrogen in the organic compound is:

In the Dumas method for the estimation of nitrogen,$0.388 \ g$ of an organic compound yielded $1.31 \ mL$ of $N_2$ gas collected at $293 \ K$ temperature and $746 \ mm$ pressure. Calculate the percentage of nitrogen in the compound. (Aqueous tension at $293 \ K = 6 \ mm$). (in $\%$)