The balanced equation is 2Al + 3PbO → Al₂O₃ + 3Pb
Al is above Pb in the activity series, so it will displace Pb from its oxide.
The unbalanced equation is
Al + PbO → Al₂O₃ + Pb
We need 2 atoms Al and 3 atoms O on each side, so the balanced equation becomes
2Al + 3PbO → Al₂O₃ + 3Pb
