To determine the number of moles of hydrochloric acid needed to react with 2.3 moles of zinc, we can use the balanced equation for the reaction:
Zn + 2HCl -> ZnCl2 + H2
From the equation, we can see that it takes 2 moles of hydrochloric acid to react with 1 mole of zinc. Therefore, we can set up a ratio:
2 moles HCl / 1 mole Zn
Now we can calculate the number of moles of hydrochloric acid needed:
2.3 moles Zn x (2 moles HCl / 1 mole Zn) = 4.6 moles HCl
Therefore, 4.6 moles of hydrochloric acid are needed to react with 2.3 moles of zinc.