Mole Conversion??????

Answer:
d
Explanation:
so in this question we need to find how many moles of H2O could be formed from 3.5 moles of oxygen.
And we know that 6 moles of H2O would be formed from 8 moles of O2 from this reaction.
By using stoichiometry we can find how many moles of H2O could be formed from 3.5 moles of oxygen since the ratio between O2 and H2O will not change even if we change the initial value of the reactants
3.50 moles of O2 * ((6 moles H2O)/(8 moles of O2))
which is d