Which of the following chemical equations is balanced?

• A. Fe + O_2 → Fe_2O_3
• B. 2 H_2 + O_2 → 2 H_2O
• C. Na + Cl_2 → 2 NaCl
• D. C_3H_8 + O_2 → 3 CO_2 + 4 H_2O

Answer: (B)

Verified step by step guidance

1. Identify the chemical equations given and write down the number of atoms of each element on both the reactant and product sides for each equation.
2. For the equation \(\mathrm{Fe + O_2 \rightarrow Fe_2O_3}\), count the number of Fe and O atoms on both sides and check if they are equal.
3. For the equation \(\mathrm{2\ H_2 + O_2 \rightarrow 2\ H_2O}\), verify that the number of hydrogen and oxygen atoms are the same on both sides.
4. For the equation \(\mathrm{Na + Cl_2 \rightarrow 2\ NaCl}\), count sodium and chlorine atoms on both sides to see if they balance.
5. For the equation \(\mathrm{C_3H_8 + O_2 \rightarrow 3\ CO_2 + 4\ H_2O}\), check the number of carbon, hydrogen, and oxygen atoms on both sides to confirm if the equation is balanced.