What are the products obtained in the electrolysis of a molten mixture of KI and KBr ?
1) K(l) and I2(g)
2) K(l) and Br2(g)
3) Br(g) and I2(g)
4) only K(l)
Iodide is more easily oxidized than bromide (iodine is less easily reduced than bromine), so we will form iodine preferentially. Such a molten mixture would be several hundred degrees Celsius, and iodine would be the diatomic gas I2 at this temperature.
We must also reduce some species in the reaction, and the only possibility here is the potassium ion. It will be reduced to potassium metal, a liquid at this temperature.
So the correct answer is 1).