Which of the following is the correctly balanced chemical equation for the reaction of sulfur dioxide with oxygen to form sulfur trioxide?

• A. 2SO2(g) + 2O2(g) → 2SO3(g)
• B. 2SO2(g) + O2(g) → 2SO3(g)
• C. SO2(g) + 2O2(g) → 2SO3(g)
• D. SO2(g) + O2(g) → SO3(g)

Answer: (B)

Verified step by step guidance

1. Identify the reactants and products in the chemical reaction: sulfur dioxide (SO2) reacts with oxygen (O2) to form sulfur trioxide (SO3).
2. Write the unbalanced chemical equation: \(\mathrm{SO_2(g) + O_2(g) \rightarrow SO_3(g)}\).
3. Balance the sulfur atoms first. Since there is one sulfur atom on each side, sulfur is already balanced.
4. Balance the oxygen atoms by adjusting coefficients. Count oxygen atoms on both sides and find the smallest whole-number coefficients that balance oxygen:
5. \$2 \mathrm{SO_2} + \mathrm{O_2} \rightarrow 2 \mathrm{SO_3}$.
6. Verify that the equation is balanced by checking that the number of atoms of each element is the same on both sides.