$0.12 \ g$ 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 $\%$)

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 ....

An organic compound is subjected to chlorination to get compound $A$. When $0.5 \ g$ of compound $A$ is reacted with $AgNO_3$ [Carius Method],it forms $0.3849 \ g$ of $AgCl$. Calculate the percentage of chlorine in compound $A$. (Round off to the nearest integer)
(Atomic masses of $Ag$ and $Cl$ are $107.87$ and $35.5$ respectively)

In Dumas method for estimation of nitrogen,$0.3 \ g$ of an organic compound gave $41.9 \ mL$ of nitrogen gas at $\text{STP}$. What is the percentage of nitrogen (in $.5$)?

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: $C=12, H=1, O=16, N=14, S=32$)

$0.53 \ g$ of an organic compound $(x)$ when heated with excess of nitric acid (concentrated) and then with silver nitrate gave $0.75 \ g$ of silver bromide precipitate. $1.0 \ g$ of $(x)$ gave $1.32 \ g$ of $CO_2$ gas on combustion. The percentage of hydrogen in the compound $(x)$ is . . . . . . $\%$. [Nearest Integer]
[Given : Molar mass in $g \ mol^{-1} H : 1, C : 12, Br : 80, Ag : 108, O : 16$; Compound $(x) : C_xH_yBr_z$] (in $\%$)