Fill in the blanks:
$(1)$ .......... gas is produced in Kjeldahl's method and absorbed in ...........
$(2)$ The excess $H_2SO_4$ is added in Kjeldahl's method and then the remaining $H_2SO_4$ is titrated with a calculated ..........

In an estimation of sulphur by Carius method, $0.2 \text{ g}$ of the substance gave $0.6 \text{ g}$ of $BaSO_4$. The percentage of sulphur in the substance is . . . . . . %. (Given molar mass in $\text{g mol}^{-1}$: $S = 32$, $BaSO_4 = 233$)

In $Duma's$ method of estimation of nitrogen,$0.35 \ g$ of an organic compound gave $55 \ mL$ of nitrogen collected at $300 \ K$ temperature and $715 \ mm$ pressure. The percentage of nitrogen in the compound is (aqueous tension at $300 \ K = 15 \ mm$). (in $.45$)

Explain Quantitative Analysis.

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?

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