When a concentrated solution of potassium iodide is electrolysed using inert electrodes, the following observations would be made:
At the anode: Iodide ions (I⁻) are oxidized to iodine (I₂) gas. This gas is a violet color, so the anode would become violet.
At the cathode: Hydroxide ions (OH⁻) are reduced to hydrogen gas (H₂) and water (H₂O). This gas is colorless, so the cathode would not change color.
In the solution: The solution would become alkaline due to the formation of hydroxide ions at the cathode. This would cause the solution to turn pink if it is added with phenolphthalein.