Which of the following is the balanced molecular equation for the reaction between nitric acid (HNO3) and calcium hydroxide (Ca(OH)2)?

• A. 2 HNO3 + Ca(OH)2 → Ca(NO3)2 + 2 H2O
• B. 2 HNO3 + Ca(OH)2 → Ca(NO3)2 + H2
• C. HNO3 + Ca(OH)2 → Ca(NO3)2 + H2O
• D. HNO3 + 2 Ca(OH)2 → Ca(NO3)2 + 2 H2O

Answer: (A)

Verified step by step guidance

1. Identify the reactants and products in the chemical reaction. The reactants are nitric acid (HNO3) and calcium hydroxide (Ca(OH)2), and the products are calcium nitrate (Ca(NO3)2) and water (H2O).
2. Write the unbalanced chemical equation: ${\mathrm{HNO}}_3+{\mathrm{Ca}\left(\mathrm{OH}\right)}_2\to {\mathrm{Ca}\left(\mathrm{NO}\right)}_3+{H\left(\mathrm{OH}\right)}_2$.
3. Balance the equation by ensuring the number of atoms of each element is the same on both sides. Start by balancing the nitrate ions (NO3). Since there are two nitrate ions in calcium nitrate, you need two nitric acid molecules: $2{\mathrm{HNO}}_3+{\mathrm{Ca}\left(\mathrm{OH}\right)}_2\to {\mathrm{Ca}\left(\mathrm{NO}\right)}_3+2{H\left(\mathrm{OH}\right)}_2$.
4. Next, balance the hydrogen and oxygen atoms. You have 2 HNO3 providing 2 hydrogen atoms and Ca(OH)2 providing 2 hydroxide ions, which combine to form 2 water molecules (H2O).
5. Verify the balanced equation: $2{\mathrm{HNO}}_3+{\mathrm{Ca}\left(\mathrm{OH}\right)}_2\to {\mathrm{Ca}\left(\mathrm{NO}\right)}_3+2{H\left(\mathrm{OH}\right)}_2$. Ensure that the number of atoms for each element is equal on both sides of the equation.