What mass of water is required to react completely with 157.35 g co2?

Assuming that the question is about making glucose, then you need to know the equation for the reaction. The equation should be: 
 
C6H12O6(s) + 6O2(g) -->6CO2(g) + 6H2O(g)

In this equation, 6 molecules of CO2 would react with 6 molecules of H2O which mean it has 1:1 ratio. The molecular weight for CO2 should be 44g/mole and H2O is 18g/mole. Then the calculation would be: 6/6 * (157.35g/44g) * 18g= 64.37g

Mgo2 is the oxidation state of manganese oxide

U whay do you need with?