Which of the following is the correct molecular equation for the reaction between calcium bromide (CaBr2) and silver nitrate (AgNO3) in aqueous solution?

• A. CaBr2 (aq) + 2 AgNO3 (aq) → AgBr (aq) + Ca(NO3)2 (s)
• B. CaBr2 (aq) + 2 AgNO3 (aq) → 2 AgBr (s) + Ca(NO3)2 (aq)
• C. CaBr2 (aq) + AgNO3 (aq) → CaBr2 (s) + AgNO3 (aq)
• D. CaBr2 (aq) + AgNO3 (aq) → AgBr (s) + Ca(NO3)2 (aq)

Answer: (B)

Verified step by step guidance

1. Identify the reactants and products in the given chemical reaction: Calcium bromide (CaBr2) and silver nitrate (AgNO3) are the reactants, while silver bromide (AgBr) and calcium nitrate (Ca(NO3)2) are the products.
2. Determine the physical states of the reactants and products: Calcium bromide and silver nitrate are both aqueous (aq), silver bromide is a solid (s) due to its low solubility in water, and calcium nitrate is aqueous (aq).
3. Write the balanced molecular equation: Ensure that the number of atoms of each element is the same on both sides of the equation. The balanced equation should reflect the stoichiometry of the reaction.
4. Check the solubility rules: Silver bromide (AgBr) is insoluble in water, which means it will precipitate out of the solution as a solid. Calcium nitrate remains in solution as it is soluble.
5. Verify the balanced equation: The correct molecular equation should be CaBr2 (aq) + 2 AgNO3 (aq) → 2 AgBr (s) + Ca(NO3)2 (aq), which shows the formation of a solid precipitate and maintains the balance of atoms.