Đáp án:

Giải thích các bước giải:`PTHH`: `CH_4+ 2O_2 `$\xrightarrow{t^o}$ `CO_2 +2H_2O``$\\$`mol`: `x`$\rightarrow$`2x`$\rightarrow$`x`$\\$`C_2H_4 + 3O_2`$\xrightarrow{t^o}$ `2CO_2 +2H_2O`$\\$`mol`: `y`$\rightarrow$`3y`$\rightarrow$`2y`$\\$`Ca(OH)_2
+CO_2`$\longrightarrow$`CaCO_3 + H_2O`$\\$ mol ``0,2``<-`0,2`<-``0,2`$\\$`n_(hh)=(3,36)/(22,4)==0,15 mol`$\\$ta co$\begin{cases} x+y=0,15\\x+2y=0,2\end{cases}$$\Rightarrow$$\begin{cases} x=0,1\\y=0,05\end{cases}$$\\$ `V_(C_2H_4)`=`0,05.22,4=1,12 lit`$\\$`%V_(C_2H_4)`=`(1,12.100%)/(3,36)`$\approx$`33,3%```