Answer
Mass of $KMnO_4$=209.22g
Work Step by Step
Mn molar mass=54.838
$KMnO_4$ molar mass=158.034
We can calculate percent composition of Mn using the formula:
Percent composition of Mn=$\frac{\text{molar mass of Mn}}{\text{Total molar mass}}\times100=\frac{54.838}{158.034}\times100\approx34.7\%$
Let Total mass of $KMnO_4$ to be $x$
Total mass of $KMnO_4$$\times\text{percent composition of Mn}=\text{mass of Mn}$
$x\times34.7\%=72.6$
$x=\frac{72.6}{34.7\%}\approx209.22g$
Mass of $KMnO_4$=209.22g
