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

In the Carius method, $0.2425 \ g$ of an organic compound gave $0.5253 \ g$ of silver chloride. The percentage of chlorine in the organic compound is: (in $\%$)

$1.4 \ g$ 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

Kjeldahl's method was used for the estimation of nitrogen in an organic compound. The ammonia evolved from $0.55 \ g$ of the compound neutralized $12.5 \ mL$ of $1 \ M \ H_2SO_4$ solution. The percentage of nitrogen in the compound is $.....$ (Nearest integer).

$0.2595 \ g$ of an organic substance in a quantitative analysis yielded $0.35 \ g$ of barium sulphate. The percentage of sulphur in the substance is $...$

$0.25 \ g$ of an organic compound $A$ containing carbon, hydrogen, and oxygen was analysed using the combustion method. The increase in mass of the $CaCl_2$ tube and the potash bulb at the end of the experiment was found to be $0.15 \ g$ and $0.1837 \ g$, respectively. The percentage of oxygen in compound $A$ is $.... \%$. (Nearest integer)
(Given: molar mass in $g \ mol^{-1}$, $H: 1, C: 12, O: 16$)