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?........$\%$

State True or False for the following statements:
$(i)$ The volume of $N_2$ is measured by nitrometer.
$(ii)$ The weight of $N_2$ is measured by nitrometer.
$(iii)$ The weight of $NH_3$ is measured by nitrometer.
$(iv)$ The volume of $NH_3$ is measured by nitrometer.

In an estimation of bromine by Carius method,$1.6 \ g$ of an organic compound gave $1.88 \ g$ of $AgBr$. The mass percentage of bromine in the compound is..........
(Atomic mass,$Ag = 108, Br = 80 \ g \ mol^{-1}$)

Consider the following reaction. On estimation of bromine in $1.00 \ g$ of $R$ using Carius method,the amount of $AgBr$ formed (in $g$) is . . . .
$\overline{[Given :}$ Atomic mass of $H = 1, C = 12, O = 16, P = 31, Br = 80, Ag = 108]$

In Kjeldahl's method for the estimation of nitrogen,the formula used is

What is the reason for passing dry air through the combustion tube during the estimation of $C$ and $H$?