标准状况下,CH4和C2H2混合气体8.96L,完全燃烧后生成26.4gCO2,则混合气体中乙炔的体积分数是多少?

CH4 xmol；C2H2 ymol
x + y = 8.96/22.4 = 0.4
x + 2y = 26.4/44 = 0.6
x = y = 0.2 mol
C2H2%=0.2/0.4=50%