Which of the following best describes the outcome of mixing NaOH (aq) and CaBr2 (aq) based on solubility rules?

• A. A precipitate of NaBr forms, and Ca(OH)2 remains in solution.
• B. Both NaOH and CaBr2 remain in solution without any reaction.
• C. No reaction occurs because all products are soluble.
• D. A precipitate of Ca(OH)2 forms, and NaBr remains in solution.

Answer: (D)

Verified step by step guidance

1. Identify the reactants in the mixture: NaOH (aq) and CaBr2 (aq).
2. Write the balanced chemical equation for the reaction: ${\mathrm{NaOH}}_{\mathrm{(aq)}}+{\mathrm{CaBr}2}_{\mathrm{(aq)}}\to {\mathrm{Ca(OH)}2}_{\mathrm{(s)}}+{\mathrm{NaBr}}_{\mathrm{(aq)}}$.
3. Apply solubility rules to determine the solubility of the products: NaBr is soluble in water, while Ca(OH)₂ is insoluble and forms a precipitate.
4. Explain why Ca(OH)₂ forms a precipitate: According to solubility rules, hydroxides of alkaline earth metals like calcium are generally insoluble in water.
5. Conclude that the correct outcome is the formation of a precipitate of Ca(OH)₂, while NaBr remains dissolved in the solution.