How many moles is 3.52 x 10²⁴ molecules of water?

5.85 moles H2O

Explanation:

(3.52 x 10^24 molecules H2O) / (1)  x (1 mole) / (6.02 x 10^23 molecules) = 5.85 moles H2O

a corroding iron, if that's one of your choices