Which of the following is the balanced chemical equation for the reaction of gaseous nitrogen dioxide with hydrogen gas to form gaseous ammonia and liquid water?

• A. NO2(g) + 3 H2(g) → NH3(g) + 2 H2O(l)
• B. 2 NO2(g) + 7 H2(g) → 2 NH3(g) + 4 H2O(l)
• C. 2 NO2(g) + 6 H2(g) → 2 NH3(g) + 3 H2O(l)
• D. NO2(g) + 2 H2(g) → NH3(g) + H2O(l)

Answer: (B)

Verified step by step guidance

1. Identify the reactants and products in the chemical reaction. The reactants are nitrogen dioxide (NO₂) and hydrogen gas (H₂), and the products are ammonia (NH₃) and water (H₂O).
2. Write the unbalanced chemical equation using the chemical formulas: NO₂(g) + H₂(g) → NH₃(g) + H₂O(l).
3. Count the number of each type of atom on both sides of the equation. For example, count the nitrogen (N), oxygen (O), and hydrogen (H) atoms in the reactants and products.
4. Adjust the coefficients of the reactants and products to balance the number of each type of atom on both sides of the equation. Start by balancing the nitrogen atoms, then the hydrogen atoms, and finally the oxygen atoms.
5. Verify that the balanced equation has the same number of each type of atom on both sides. The balanced equation should be: 2 NO₂(g) + 7 H₂(g) → 2 NH₃(g) + 4 H₂O(l).