During the estimation of $C$ and $H$,the $H_2O$ produced is absorbed in which of the following?

In the estimation of nitrogen,$0.3 \ g$ of an organic compound was digested,and the evolved ammonia was passed into $100 \ mL$ of $0.1 \ M \ H_2SO_4$. The excess acid required $20 \ mL$ of $0.5 \ M \ NaOH$ for complete neutralization. What is the organic compound?

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

During the quantitative estimation of $C$ and $H$,the $CO_2$ produced is absorbed in which of the following?

In the estimation of halogens by the Carius method,the halogen present in the organic compound is converted into which of the following?

$0.5 \ g$ of an organic compound containing phosphorus was heated with conc. $HNO_3$ in a Carius tube. The phosphoric acid thus formed was precipitated with magnesia mixture $[MgNH_4PO_4]$,which on ignition gave a residue of $1.0 \ g$ of magnesium pyrophosphate $(Mg_2P_2O_7)$. The percentage of phosphorus in the organic compound is: