Given
Volume of N2, Alkane, O2 is 10 ml
Solution
Reaction of N2, CnH2n+2, O2 gives CO2
CO2 is absorbed by KOH
Volume contracted = 2ml
Hence Volume of CO2 = 2ml
Now in tube only N2 and Alkane is left
When N2 is reacted with excess of H2 it forms NH3.
The correct option is D