An ideal gaseous mixture of ethane (C2H6) and ethene (C2H4) occupies 28 liter at 1atm and 273 K. The mixture reacts completely with 128 gm O2 to produce CO2 and H2O. Mole fraction at C2H4 in the mixture is

Moles of C2H6 and C2H4 are a and b respectively a+b=2822.4=1.25C2H6(g)a+3.5O2(g)⟶2CO2(g)+3H2O(l)  C2H4b(g)+3O2(g)⟶2CO2(g)+2H2O(l)  Moles of O2=3.5a+3b=4                       a+b=1.25a=0.5b=0.75mole fraction of C2H4 , XC2H4=nbn=0.751.25=0.6