Question

Aluminum + silver sulfide = ?
a) what element is reduced and what is its charge before and after?
b) what element is oxidized and what is its charge before and after?

Answer 1

2Al + 3Ag₂S → 6Ag + Al₂S₃
a) Silver is reduced. Ag⁺ + 1e → Ag⁰; its charge is +1 before and becomes zero after.
b) Aluminum is oxidized. Al⁰ – 3e → Al³⁺; its charge is zero before and becomes +3 after.