In the $Dumas$ method,the nitrogen-containing organic compound is first heated with which of the following?

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 ..........

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)

Which of the following substances cannot be analyzed using the Kjeldahl method for the estimation of nitrogen?

Kjeldahl's method cannot be used to estimate nitrogen for which of the following compounds?

What are the formulas,names,and molecular masses of the compounds obtained during the estimation of phosphorus in organic compounds?