JEE Main levelSingle correct optionDifficulty 2 of 3ec033
The spontaneous reaction Zn(s)+2FeX3+(aq)ZnX2+(aq)+2FeX2+(aq) is to be run in a galvanic cell. The correct cell notation is
AZn∣ZnX2+∣∣FeX3+,FeX2+∣Pt
BZn∣ZnX2+∣∣FeX3+∣FeX2+
CPt∣FeX2+,FeX3+∣∣ZnX2+∣Zn
DZn∣ZnX2+∣∣FeX2+∣Fe
Answer: A
Zn is oxidised, so Zn∣ZnX2+ is the anode and is written on the left. The cathode half reaction FeX3++eX−FeX2+ has both species in solution, so an inert Pt electrode is needed and the two ions are separated by a comma, not a vertical line. Option B has no electrode, option C is reversed (would have negative EMF), option D reduces FeX2+ to Fe, which is a different reaction.