The transformation occurring in Dumas's method is given below:
$C_{2}H_{7}N + (2x + \frac{y}{2})CuO \rightarrow xCO_{2} + \frac{y}{2}H_{2}O + \frac{z}{2}N_{2} + (2x + \frac{y}{2})Cu$
The value of $y$ is ...... .(Integer answer)

The number of moles of $CuO$ that will be utilized in the Dumas method for the estimation of nitrogen in a sample of $57.5 \ g$ of $N,N$-dimethylaminopentane is $..... \times 10^{-2}$. (Nearest integer)

$0.5 \ g$ 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:

Describe the Kjeldahl's method and the principles for the estimation of nitrogen present in an organic compound.

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 the Dumas method for the estimation of nitrogen,$0.388 \ g$ of an organic compound yielded $1.31 \ mL$ of $N_2$ gas collected at $293 \ K$ temperature and $746 \ mm$ pressure. Calculate the percentage of nitrogen in the compound. (Aqueous tension at $293 \ K = 6 \ mm$). (in $\%$)