In Dumas method for estimating nitrogen in organic compound, the gas finally collected is

The CO2 H2O released in the above experiment is absorbed by  aq. KOH solution which is taken in nitrometer. The N2 gas collected at the top of the nitrometer [graduated tube]. The volume of N2 collected in graduated tube is called experimental volume, which is denoted by "V1"  [vml].→ Experimental volume we need to convert into STP volume