The unfavourable electrochemical reaction among the following is: — p Block Elements Chemistry Question

💡 Solution & Explanation

Step 1: Electrochemical feasibility of displacement reactions depends on the relative reduction potentials or the activity of the halogens. Step 2: Chlorine is a much stronger oxidizing agent than iodine (E° Cl2/Cl- = +1.36 V, E° I2/I- = +0.54 V). Therefore, Cl2 can easily displace I- from KI (reaction b), but the weaker oxidizing agent I2 cannot displace Cl- from KCl (reaction c). Step 3: Thus, the reaction KCl + I2 -> KI + ICl is highly unfavourable/non-spontaneous, making option (c) the correct choice.