Answer:
D. 16.5 moles
Explanation:
From the balanced reaction we know that 1 mole of Zn reacts with 2 moles of HCl.
We can calculate the moles of HCl needed to react completely with 8.25 moles of zinc, using the stoichiometry of the reaction and a mathematical rule of three:
[tex]\begin{gathered} 1moleZn-2molesHCl \\ 8.25molesZn-x=\frac{8.25molesZn*2molesHCl}{1moleZn} \\ x=16.5molesHCl \end{gathered}[/tex]So, 16.5 moles of HCl are needed.