1. Write the Balanced Chemical Equation
Calcium hydroxide (Ca(OH)₂) reacts with hydrobromic acid (HBr) to form calcium bromide (CaBr₂) and water (H₂O):
Ca(OH)₂ (aq) + 2 HBr (aq) → CaBr₂ (aq) + 2 H₂O (l)
2. Identify the Ions in Solution
* Calcium hydroxide (Ca(OH)₂): Dissociates into Ca²⁺(aq) and 2OH⁻(aq) ions.
* Hydrobromic acid (HBr): Dissociates into H⁺(aq) and Br⁻(aq) ions.
* Calcium bromide (CaBr₂): Dissociates into Ca²⁺(aq) and 2Br⁻(aq) ions.
3. Determine Spectator Ions
Spectator ions are ions that are present on both sides of the reaction equation and do not participate in the formation of the precipitate or the production of water.
In this reaction, the calcium ions (Ca²⁺) and the bromide ions (Br⁻) are present on both sides of the equation. They remain unchanged throughout the reaction.
4. Answer
Therefore, the spectator ions in the reaction between calcium hydroxide and hydrobromic acid are a) calcium ions (Ca²⁺) and b) bromide ions (Br⁻).
