Nitrogen present in an unknown organic compound was estimated by the Dumas method to be $17.7 \%$ by weight. The compound is very likely to be ....

$0.12 \ g$ of an organic compound '$X$' containing phosphorus on reacting with magnesia mixture gave $0.22 \ g$ of magnesium pyrophosphate $(Mg_2P_2O_7)$. The percentage of phosphorus in the compound '$X$' is (in $\%$)

In the estimation of $C$ and $H$ by Liebig's method,is $H_2O$ absorbed before $CO_2$? Why?

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

In the Kjeldahl method,$0.35 \ g$ of an organic compound produces ammonia,which is absorbed in $100 \ mL$ of $0.1 \ M \ H_2SO_4$. The excess $H_2SO_4$ requires $154 \ mL$ of $0.1 \ M \ NaOH$ for titration. Calculate the percentage of nitrogen in the compound. (Given atomic masses: $C=12, H=1, O=16, N=14, S=32$)

$29.5 \ mg$ 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 $..... \%$.