Consider galvanic cell, ^ A _ ( s ) | A _ ( aq ) ⁺² | | B _ ( aq ) ⁺ | B _ ( s ) ^ if emf of cell is positive, identify a correct cell reaction from following.

Step-by-step solution

Cell notation follows the convention: anode | anode ions || cathode ions | cathode. The anode is written on the left (marked as negative) where oxidation occurs, and the cathode on the right (marked as positive) where reduction occurs. Given the notation A _ ( s ) ^ | A _ ( aq ) ⁺² || B _ ( aq ) ⁺ | B _ ( s ) ^ , the half-reactions are: Oxidation: A _ ( s ) A _ ( aq ) ⁺² + 2 e ⁻ Reduction: B _ ( aq ) ⁺ + e ⁻ B _ ( s ) To balance electrons, multiply the reduction half-reaction by 2: 2 B _ ( aq ) ⁺ + 2 e ⁻ 2 B _ ( s