Which method uses an instrument called a nitrometer?

$1.4 \ g$ of an organic compound was digested according to Kjeldahl's method and the ammonia evolved was absorbed in $60 \ mL$ of $M/10 \ H_2SO_4$ solution. The excess sulphuric acid required $20 \ mL$ of $M/10 \ NaOH$ solution for neutralization. The percentage of nitrogen in the compound is

The Kjeldahl method of nitrogen estimation fails for which of the following reaction products $?$
$(a)$ Nitrobenzene $\xrightarrow{Sn/HCl}$ Aniline
$(b)$ Benzonitrile $\xrightarrow{LiAlH_4}$ Benzylamine
$(c)$ Benzyl cyanide $\xrightarrow{(i) SnCl_2 + HCl, (ii) H_2O}$ Phenylacetaldehyde
$(d)$ Aniline $\xrightarrow{NaNO_2/HCl}$ Benzenediazonium chloride

$0.3 \ g$ of an organic compound gave $50 \ mL$ of nitrogen collected at $300 \ K$ and $715 \ mm$ pressure in Dumas method. Calculate the percentage of nitrogen in the compound (aqueous tension of water at $300 \ K$ is $15 \ mm$).

Dumas method involves the determination of nitrogen content in the organic compound in the form of

Nitrogen present in an unknown organic compound was estimated by the Dumas method to be $17.7 \%$ by weight. The compound is very likely to be ....