Kjeldahl's method cannot be used to estimate nitrogen for which of the following compounds?

In the estimation of nitrogen by Kjeldahl's method,$2.8 \ g$ of an organic compound required $20 \ mmol$ of $H_2SO_4$ for the complete neutralisation of $NH_3$ gas evolved. The percentage of nitrogen in the sample is?........$\%$

Which method uses an instrument called a nitrometer?

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

$0.2 \ g$ 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 $STP$ : $22.4 \ L \ mol^{-1}$ )

$58 \ mL$ of $\frac{N}{5} \ H_2SO_4$ are used to neutralize ammonia given by $1 \ g$ of an organic compound. The percentage of nitrogen in the compound is: