How does the oxidation number for lead (Pb) change?

Question

PbO₂ + 4H⁺ + SO₄^2– + 2e^– → PbSO₄ +2H₂O

Answer 1

In PbO_2, you can determine the Pb charge because oxygen almost always has a charge of -2.

-2 x 2 = -4, so the charge for Pb must be +4

In PbSO_4, the sulfur can trip you up, but don't let it. Remember, the anion you're actually dealing with is

SO₄^-2, which is actually the sulfate anion. Knowing that, it's easy to see that the Pb changed to a charge of +2.

TLDR: Pb +4 -----> Pb +2