From $0.50 \ g$ of an organic compound,ammonia is evolved and absorbed in $50 \ mL$ of $0.5 \ M \ H_2SO_4$. In the titration of the excess $H_2SO_4$,$60 \ mL$ of $0.5 \ M \ NaOH$ is used. Calculate the percentage of nitrogen in the compound. (in $\%$)

In the Carius method for the estimation of halogen,$0.172 \ g$ of an organic compound showed the presence of $0.08 \ g$ of bromine. Which of these is the correct structure of the compound?

$29.5 \ mg$ of an organic compound containing nitrogen was digested according to Kjeldahl's method and the evolved ammonia was absorbed in $20 \ mL$ of $0.1 \ M \ HCl$ solution. The excess of the acid required $15 \ mL$ of $0.1 \ M \ NaOH$ solution for complete neutralization. The percentage of nitrogen in the compound is $..... \%$.

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

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 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).