How can you identify the anode and cathode of a car battery of indistinct shape by using a potassium iodide solution?
By using the battery as a source of electricity in an electrolytic cell that contains potassium iodide as an electrolyte.
Electrolysis takes place where iodide ion is oxidized at anode and brown colour of iodine solution appears at anode.
At cathode hydrogen gas evolves which is indicated by formation of bubbles at cathode.