\(n_{O_2}=\dfrac{6,72}{22,4}=0,3\left(mol\right)\\ PTHH:2KMnO_4\underrightarrow{t^o}O_2\uparrow+MnO_2+K_2MnO_4\\ Mol:0,6\leftarrow0,3\\ 2KClO_3\underrightarrow{t^o,MnO_2}3O_2\uparrow+2KCl\\ Mol:0,2\leftarrow0,3\\ \Rightarrow\left\{{}\begin{matrix}m_{KMnO_4}=0,6.158=94,8\left(g\right)\\m_{KClO_3}=0,2.122,5=24,5\left(g\right)\end{matrix}\right.\\ \Rightarrow m_{KMnO_4}>m_{KClO_3}\)
nKClO3 phản ứng=23nO2=0,2(mol)⇒nKClO3 cần dùng=0,270%=27(mol)⇒mKClO3 cần dùng=27.122,5=35(gam