Some standard electrode potentials at 298 K are: Pb²⁺/Pb −0.13 V, Ni²⁺/Ni −0.24 V, Cd²⁺/Cd −0.40 V and Fe²⁺/Fe −0.44 V. To a solution containing 0.001 M of X²⁺ and 0.1 M of Y²⁺, metal rods X and Y are inserted at 298 K and connected by a conducting wire. This resulted in dissolution of X. The correct combination(s) of X and Y, respectively, is(are). Given R = 8.314 J K⁻¹ mol⁻¹ and F = 96500 C mol⁻¹.