15. The following is the unbalanced chemical equation for the reaction between sodium
metal and water:
Na(s) + H$_2$O(l) → NaOH(aq) + H$_2$(g)
After balancing the reaction, how many moles of hydrogen gas are produced if one mole of
water takes part in the reaction?
a. 0.5
b. 1
c. 2
d. 4