Sulfurous acid, H2SO3, breaks down into water (H2O) and sulfur dioxide (SO2).If only one molecule of sulfurous acid was involved in a chemical reaction, how many sulfur (S) atoms would be in the products?

One molecule of H₂SO₃ contains one sulfur atom. When it breaks down into H₂O and SO₂, that sulfur atom is in the SO₂ product, so the products contain 1 sulfur atom. The correct choice is A, 1 atom of sulfur.

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