Question

A hypothetical galvanic cell is A$_{(s)}$ | A$^+$(1M) || B$^{+2}$(1M) | B$_{(s)}$ and emf of cell is positive. What is the possible cell reaction?

• A. A$_{(s)}$ + B$^{+B}_{(aq)}$ $\rightarrow$ A$^{+1}_{(aq)}$ + B$_{(s)}$
• B. 2A$_{(s)}$ + B$^{+2}_{(aq)}$ $\rightarrow$ 2A$^{+1}_{(aq)}$ + B$_{(s)}$
• C. A$_{(s)}$ + 2B$^{+2}_{(aq)}$ $\rightarrow$ A$^{+1}_{(aq)}$ + 2B$_{(s)}$
• D. 2A$^{+1}_{(aq)}$ + B$_{(s)}$ $\rightarrow$ 2A$_{(s)}$ + B$^{+2}_{(aq)}$

Hint:

A spontaneous cell reaction must always have the oxidation half-reaction at the anode and the reduction half-reaction at the cathode, with balanced electrons.

Answer 1

The Correct Option is B

Step 1: Identify Half-Reactions
Anode (Oxidation): $A_{(s)} \rightarrow A^+_{(aq)} + e^-$
Cathode (Reduction): $B^{2+}_{(aq)} + 2e^- \rightarrow B_{(s)}$
Step 2: Balance Electrons
Multiply the anode reaction by 2:
$2A_{(s)} \rightarrow 2A^+_{(aq)} + 2e^-$
Step 3: Add Reactions
$2A_{(s)} + B^{2+}_{(aq)} \rightarrow 2A^+_{(aq)} + B_{(s)}$.
Step 4: Conclusion
Option (B) represents the correctly balanced spontaneous cell reaction.
Final Answer:(B)