In the estimation of nitrogen by Kjeldahl's method,$2.8 \ g$ of an organic compound required $20 \ mmol$ of $H_2SO_4$ for the complete neutralisation of $NH_3$ gas evolved. The percentage of nitrogen in the sample is?........$\%$

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

Column-$I$	Column-$II$
$(i).$ Magnesium pyrophosphate	$(a).$ $I_2O_5$
$(ii).$ Barium sulphate	$(b).$ $AgX$
$(iii).$ Iodide pentoxide	$(c).$ $Mg_2P_2O_7$
$(iv).$ Silver halide	$(d).$ $BaSO_4$

In Dumas method for the estimation of $N_2$,the sample is heated with copper oxide and the gas evolved is passed over :

$A$ student has been given $0.314 \ g$ of an organic compound and asked to estimate Sulphur. During the experiment, the student has obtained $0.4813 \ g$ of barium sulphate. The percentage of sulphur present in the compound is . . . . . .
(Given Molar mass in $g \ mol^{-1}$: $S = 32$, $BaSO_4 = 233$) (in $\%$)

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 Carius method of estimation of halogens,$250 \ mg$ of an organic compound gave $141 \ mg$ of $AgBr$. The percentage of bromine in the compound is: