Determine the number of moles of al needed to completely react with 9.0 moles of ni2

6.0 moles

Explanation:

1) The information in the quesiton is incomplete.

2) The question is bases on a voltaic cell in which the reactants are

Al (NO₃) ₃ (aq) + Ni (NO₃) ₂ (aq).

3) And you are also given the net ionic reaction:
2Al(s) + 3Ni²⁺ (aq) → 2Al₃ (aq) + 3Ni(s)

4) It is from the net ionic reaction that you get the ration between Al and Ni:
2 moles of Al react with 3 moles of Ni, so you can state the proportion:

2 moles Al / 3 moles Ni = x / 9.0 moles Ni

5) So, you just must solve for x:

x = 9.0 moles Ni × 2 moles Al / 3 mols Ni = 6.0 moles Al

The reaction will shift to the right