\(m_{C_2H_4}=5.6\left(g\right)\)
\(n_{C_2H_4}=\dfrac{5.6}{28}=0.2\left(mol\right)\)
\(C_2H_4+Br_2\rightarrow C_2H_4Br_2\)
\(V_{CH_4}=11.2-0.2\cdot22.4=6.72\left(l\right)\)
\(n_{CH_4}=\dfrac{6.72}{22.4}=0.3\left(mol\right)\)
\(m_{CH_4}=0.3\cdot16=4.8\left(g\right)\)
\(CH_4+2O_2\underrightarrow{t^0}CO_2+2H_2O\)
\(C_2H_4+3O_2\underrightarrow{t^0}2CO_2+2H_2O\)
\(V_{O_2}=\left(0.3\cdot2+0.2\cdot3\right)\cdot22.4=26.88\left(l\right)\)