Question

Consider galvanic cell, \({ }^{\ominus} \mathrm{A}_{(\mathrm{s})}\left|\mathrm{A}_{(\mathrm{aq})}^{+2}\right|\left|\mathrm{B}_{(\mathrm{aq})}^{+}\right| \mathrm{B}_{(\mathrm{s})}^{\oplus}\)

if emf of cell is positive, identify a correct cell reaction from following.

• A. \(\mathrm{A}_{(\mathrm{s})}+\mathrm{B}_{(\mathrm{aq})}^{+2}\longrightarrow \text{ }\mathrm{A}_{(\mathrm{aq})}^{+2}+\mathrm{B}_{(\mathrm{s})}\)
• B. \(\mathrm{A}_{(\mathrm{s})}+2\text{ }\mathrm{B}_{(\mathrm{aq})}^{+}\longrightarrow \mathrm{A}_{(\mathrm{aq})}^{+2}+2\text{ }\mathrm{B}_{(\mathrm{s})}\)
• C. \(2\text{ }\mathrm{A}_{(\mathrm{aq})}^{+2}+\mathrm{B}_{(\mathrm{s})}\longrightarrow 2\text{ }\mathrm{A}_{(\mathrm{s})}+\mathrm{B}_{(\mathrm{aq})}^{+}\)
• D. \(2\text{ }\mathrm{A}_{(\mathrm{s})}+\mathrm{B}_{(\mathrm{aq})}^{+}\longrightarrow 2\text{ }\mathrm{A}_{(\mathrm{aq})}^{+2}+\mathrm{B}_{(\mathrm{s})}\)

Hint:

In the cell notation the left electrode is the anode and the right is the cathode; write oxidation on the left and reduction on the right.

Answer 1

The Correct Option is B

Step 1: Understanding the Concept
In the notation \(\text{A}|\text{A}^{2+}\,||\,\text{B}^{+}|\text{B}\), A is the anode (oxidation) and B is the cathode (reduction).

Step 2: Half Reactions
Anode: \(\text{A} \rightarrow \text{A}^{2+} + 2\text{e}^{-}\)
Cathode: \(\text{B}^{+} + \text{e}^{-} \rightarrow \text{B}\)

Step 3: Overall Reaction
Multiply the cathode half reaction by 2 so the electrons cancel:
\(\text{A} + 2\text{B}^{+} \rightarrow \text{A}^{2+} + 2\text{B}\)

Final Answer:
The cell reaction is A plus 2B+ giving A2+ plus 2B. \[ \boxed{\text{(B) }\text{A}_{(s)} + 2\,\text{B}^{+}_{(aq)} \rightarrow \text{A}^{+2}_{(aq)} + 2\,\text{B}_{(s)}} \]