a, \(C_2H_4+Br_2\rightarrow C_2H_4Br_2\)
b, Ta có: \(n_{C_2H_4Br_2}=\dfrac{9,4}{188}=0,05\left(mol\right)\)
Theo PT: \(n_{C_2H_4}=n_{C_2H_4Br_2}=0,05\left(mol\right)\)
\(\Rightarrow\left\{{}\begin{matrix}\%V_{C_2H_4}=\dfrac{0,05.22,4}{5,6}.100\%=20\%\\\%V_{CH_4}=80\%\end{matrix}\right.\)