Q. A hypothetical electrochemical cell is shown below A | A⁺ (xM) || B⁺ (yM) | B The emf measured is +0.20 V. The cell reaction is :
A) A⁺ + B → A + B⁺
B) A⁺ + e⁻ → A; B⁺ + e⁻ → B
C) the cell reaction cannot be predicted
D) A + B⁺ → A⁺ + B
Explanation
[Solution from source] In the cell notation the left electrode is the anode (oxidation) and the right the cathode (reduction). A positive emf of +0.20 V means this cell is spontaneous as written: A → A⁺ + e⁻ and B⁺ + e⁻ → B, i.e. A + B⁺ → A⁺ + B. The reverse reaction would have a negative emf. Answer (4).
Reviewed by Dr. Abubacker
Physics Educator & NEET/JEE Specialist
Ph.D. in Physics with 19+ years of teaching experience.