During the estimation of $C$ and $H$,the $H_2O$ produced is absorbed in which of the following?

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

Explain the Carius method and its principle for the estimation of halogen elements.

Discuss the principle of estimation of halogens,sulphur and phosphorus present in an organic compound.

Why is a solution of potassium hydroxide used to absorb carbon dioxide evolved during the estimation of carbon present in an organic compound?

In the estimation of sulphur by Carius method,$0.468 \,g$ of an organic sulphur compound afforded $0.668 \,g$ of barium sulphate. Find out the percentage of sulphur in the given compound. (in $\%$)