Correct Products and Notation in Roasting Reaction

Steps:

• Identify reactants: PbS and O₂ from air.
• Identify products: SO₂ (sulfur oxidized) and PbO (lead remains +2).
• Check oxidation: Sulfur from -2 to +6 in SO₂; lead +2 in PbO, not PbO₂.
• Select equation with correct products and standard → arrow.

Why C is correct:

• Matches the reaction forming PbO (lead(II) oxide) and SO₂, using proper → for irreversible process.

Why the others are wrong:

• A: Wrong product PbO₂ (lead(IV) oxide) violates lead's +2 state.
• B: Wrong product PbO₂ and uses = (equilibrium, not reaction direction).
• D: Identical to C but listed separately; C is specified as correct.

Final answer: C