Etilen tham gia phản ứng với brom trong dd.
$n_{Br_2\text{pứ}}=n_{Br_2\text{giảm}}=\dfrac{16}{160}= 0,1(mol)$
$C_2H_4+Br_2\to BrCH_2-CH_2Br$
$\to n_{C_2H_4}=n_{Br_2}=0,1(mol)$
$\to V_{C_2H_4}=0,1.22,4=2,24l$
$\%V_{C_2H_4}=\dfrac{2,24.100}{4,48}=50\%$
$\to \%V_{C_2H_6}=100\%-50\%=50\%$