Which of the following best describes the balanced chemical equation for the decomposition of water?

• A. 2H2O → H2 + 2O2
• B. 2H2O → 2H2 + O2
• C. H2O → 2H2 + O2
• D. H2O → H2 + O2

Answer: (B)

Verified step by step guidance

1. Identify the chemical species involved in the decomposition of water: water (H2O) decomposes into hydrogen gas (H2) and oxygen gas (O2).
2. Write the unbalanced chemical equation for the decomposition: \(\mathrm{H_2O \rightarrow H_2 + O_2}\).
3. Balance the hydrogen atoms first. Since each water molecule has 2 hydrogen atoms and hydrogen gas (H2) has 2 atoms per molecule, balance the number of H2 molecules accordingly.
4. Balance the oxygen atoms next. Each water molecule has 1 oxygen atom, and oxygen gas (O2) has 2 atoms per molecule, so adjust the coefficients to balance oxygen atoms on both sides.
5. Ensure that the coefficients are the smallest whole numbers that balance both hydrogen and oxygen atoms, resulting in the balanced equation.