3al + 3nh4clo4 → al2o3 + alcl3 + 3no + 6h2o

how many moles of water are produced from 373 mol al?

Once we have moles, we can use mole-to-mole ratio from the balanced equation to convert from one molecule to the other. 

3 mol of Al= 6 mol of H₂O

The activity series is shown in the attached picture. if the element is below the other, then you can displace the other. following the activity series as a guide, the reactions are as follows: nickel and aluminum chloride3 ni + 2 alcl₃  → 3 nicl₂ + 2 albarium and copper bromideba + cubr  →  no reaction because cu is less oxidizable than bapotassium nitrate and aluminum3 kno₃ + al  → al(no₃)₃ + 3 ksodium phosphate and zincnaso₄ + zn  → znso₄ + na