To answer this question, you need to know the equation of the reaction. I think the equation should be
3K2MnO4 + 2 CO2 = 2 KMnO4 +1 MnO2 + 2 K2CO3
If you look at the coefficient, for every 2 CO2 there will be 2 KMnO4 formed. The amount of KMnO4 formed for 0.886 CO2 with 100% yield would be:
2/2 * 0.886 moles= 0.886 moles
