Multiple Choice
What is the balanced half-reaction for the oxidation occurring at the anode in the galvanic cell: Co(s) | Co2+(aq) || Cu2+(aq) | Cu(s) in an acidic solution?
6. Chemical Quantities & Aqueous Reactions
Balancing Redox Reactions: Acidic Solutions
Multiple Choice
A 10.00-mL sample of a 0.130 M H3PO4 solution is added to 13.00 mL of a 0.150 M Ba(OH)2 solution. When the reaction is complete, what spectator ions are present?2 H3PO4 (aq) + 3 Ba(OH)2 (aq) → Ba3(PO4)2 (s) + 6 H2O (l)
A
[H]+
B
[PO4]3–
C
[Ba]2+
D
[OH]–
E
All of the above ions are present.
F
No spectator ions are present.
Verified step by step guidance1
Identify the balanced chemical equation for the reaction: \(2 \text{H}_3\text{PO}_4 (aq) + 3 \text{Ba(OH)}_2 (aq) \rightarrow \text{Ba}_3\text{(PO}_4)_2 (s) + 6 \text{H}_2\text{O} (l)\).
Understand that spectator ions are ions that do not participate in the formation of the precipitate or any other product in the reaction. They remain in the solution unchanged.
Examine the balanced equation: \(\text{Ba}_3\text{(PO}_4)_2\) is a solid precipitate, indicating that \([\text{Ba}^{2+}]\) and \([\text{PO}_4^{3-}]\) ions are involved in forming the precipitate.
Since \([\text{Ba}^{2+}]\) and \([\text{PO}_4^{3-}]\) are part of the precipitate, they are not spectator ions. \([\text{H}^+]\) and \([\text{OH}^-]\) ions react to form water, so they are also not spectator ions.
Conclude that there are no ions left in the solution that do not participate in the reaction, meaning there are no spectator ions present.
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