Quantitative measurement of nitrogen in an organic compound is done by the method:

$0.25 \ g$ 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 $g \ mol^{-1}$, $H: 1, C: 12, O: 16$)

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 sulphur estimation, $2.0 \times 10^{-3}$ mol of an organic compound $(X)$ (molar mass $76 \text{ g mol}^{-1}$) gave $0.4813 \text{ g}$ of barium sulphate (molar mass $233 \text{ g mol}^{-1}$). The percentage of sulphur in the compound $(X)$ is . . . . . . $\% \times 10^{-1}$ (Nearest integer).

The reaction of $Q$ with $PhSNa$ yields an organic compound (major product) that gives a positive Carius test on treatment with $Na_2O_2$ followed by the addition of $BaCl_2$. The correct option$(s)$ for $Q$ is (are):

In the Carius method,$0.099 \, g$ of an organic compound gave $0.287 \, g$ of $AgCl$. The percentage of chlorine in the compound is: