\(a,V_{CH_4}=\dfrac{2}{2+3}.11,2=4,48\left(l\right)\\ V_{C_2H_6}=11,2-4,48=6,72\left(l\right)\\ n_{CH_4}=\dfrac{4,48}{22,4}=0,2\left(mol\right);n_{C_2H_6}=\dfrac{6,72}{22,4}=0,3\left(mol\right)\\ b,m_{hh}=m_{CH_4}+m_{C_2H_6}=16.0,2+30.0,3=12,2\left(g\right)\)