Which of the following chemical equations is balanced?

• A. C_3H_8 + O_2 ightarrow 3 CO_2 + 4 H_2O
• B. Na + Cl_2 ightarrow 2 NaCl
• C. 2 H_2 + O_2 ightarrow 2 H_2O
• D. N_2 + 2 H_2 ightarrow NH_3

Answer: (C)

Verified step by step guidance

1. Step 1: Understand that a balanced chemical equation has the same number of atoms of each element on both the reactant and product sides.
2. Step 2: For each given equation, count the number of atoms of each element on the reactant side and compare it to the number on the product side.
3. Step 3: For example, in the equation \(\mathrm{C_3H_8 + O_2 \rightarrow 3\ CO_2 + 4\ H_2O}\), count carbon (C), hydrogen (H), and oxygen (O) atoms on both sides to check if they are equal.
4. Step 4: Repeat this process for each equation: \(\mathrm{Na + Cl_2 \rightarrow 2\ NaCl}\), \(\mathrm{2\ H_2 + O_2 \rightarrow 2\ H_2O}\), and \(\mathrm{N_2 + 2\ H_2 \rightarrow NH_3}\).
5. Step 5: Identify which equation has equal numbers of atoms for every element on both sides, confirming it is balanced.