Đặt số mol CH4; C2H4; C2H2 lần lượt là x;y;z ( mol )
\(\Rightarrow m_X=16x+28y+26z=17,2\left(g\right)\) (1)
\(CH_2=CH_2+Br_2\rightarrow CH_2Br-CH_2Br\)
y y ( mol )
\(CH\equiv CH+2Br_2\rightarrow CHBr_2-CHBr_2\)
z 2z ( mol )
\(n_{Br_2}=y+2z=\dfrac{96}{160}=0,6\left(mol\right)\) ( 2)
Đặt phần sau bằng k lần phần đầu
\(n_{hhk}=kx+ky+kz=\dfrac{6,72}{22,4}=0,3\left(mol\right)\) (3)
\(n_{AgC\equiv AgC}=\dfrac{18}{240}=0,075\left(mol\right)\)
\(CH\equiv CH+Ag_2O\underrightarrow{ddNH_3}AgC\equiv AgC\downarrow+H_2O\)
0,075 0,075 ( mol )
\(\Rightarrow kz=0,075\left(mol\right)\) (4)
\(\dfrac{\left(3\right)}{\left(4\right)}\Rightarrow\dfrac{kx+ky+kz}{kz}=\dfrac{0,3}{0,075}=4\)
\(\Leftrightarrow x+y+z=4z\)
\(\Leftrightarrow x+y-3z=0\) (5)
\(\left(1\right);\left(2\right);\left(5\right)\Rightarrow\left\{{}\begin{matrix}x=0,4\\y=0,2\\z=0,2\end{matrix}\right.\)
\(\%V_{CH_4}=\dfrac{0,4}{0,4+0,2+0,2}.100=50\%\)
`->` Chọn A
