In Carius method for estimation of halogens,$180 \ mg$ of an organic compound produced $143.5 \ mg$ of $AgCl$. The percentage composition of chlorine in the compound is $............. \%$.
[Given : molar mass in $g \ mol^{-1}$ of $Ag = 108$,$Cl = 35.5$]

Calculate the percentage of nitrogen in $0.25 \ g$ of an organic compound if $38 \ cm^3$ of $N_2$ gas is evolved at $300 \ K$ and $96 \ kPa$ pressure. (Given: $1 \ atm = 101.3 \ kPa$)

Match column $-I$ and column $-II$ with the correct relation:

Column $-I$	Column $-II$
$(i)$ Dumas method	$(a)$ Absorption of $NH_3$ in $H_2SO_4$
$(ii)$ Kjeldahl's method	$(b)$ $BaCl_2$ by added $BaSO_4$
$(iii)$ Carius method	$(c)$ Mixture of Magnesia
$(iv)$ Estimation of phosphorus	$(d)$ $N_2$

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

Describe the principle and reactions involved in the estimation of oxygen in an organic compound.

$A$ sample of $0.50 \, g$ of an organic compound was treated according to Kjeldahl's method. The ammonia evolved was absorbed in $50 \, mL$ of $0.5 \, M \, H_{2}SO_{4}$. The residual acid required $60 \, mL$ of $0.5 \, M \, NaOH$ solution for neutralisation. Find the percentage composition of nitrogen in the compound. (in $\%$)