\(3C_2H_4+4H_2O+2KMnO_4\rightarrow2KOH+2MnO_2+3C_2H_4\left(OH\right)_2\)
0,3__________________________________0,2________________
\(n_{MnO2}=\frac{17,4}{87}=0,2\left(mol\right)\)
\(\Rightarrow n_{C2H4}=0,3\left(mol\right)\)
\(\Rightarrow V_{C2H4}=0,3.22,4=6,72\left(l\right)\)