Consider an electrochemical cell involving the overall reaction 2agbr(s) + pb(s) → pb2 + 2ag(s) + 2br–. each half-reaction is carried out in a separate compartment. the anion included in the lead half-cell is no3–. the cation in the silver half-cell is k . the two half-cells are connected by a kno3 salt bridge. if [pb2+] = 1.0 m, what concentration of br– ion will produce a cell emf of 0.25 v at 298 k?
given: agbr(s) + e– → ag + br–, e° = +0.07 v.