a)
PTHH: C2H2+2Br2 --> C2H2Br4
b) \(n_{C_2H_2}=\dfrac{36}{26}=\dfrac{18}{13}\left(mol\right)\)
=> \(V_{C_2H_2}=\dfrac{18}{13}.22,4=\dfrac{2016}{65}\left(l\right)\)
\(n_{CH_4}=\dfrac{42-36}{16}=0,375\left(mol\right)\)
=> \(V_{CH_4}=0,375.22,4=8,4\left(l\right)\)
c) \(\left\{{}\begin{matrix}\%V_{C_2H_2}=\dfrac{\dfrac{2016}{65}}{\dfrac{2016}{65}+8,4}.100\%=78,69\%\\\%V_{CH_4}=\dfrac{8,4}{\dfrac{2016}{65}+8,4}.100\%=21,31\%\end{matrix}\right.\)