A galvanic cell employs a lead electrode in 1.0 M Pb(NO₃)₂ and a silver electrode in…
CHEMISTRY · Single correct · A Level · Chemistry · Electrode potentials · Electrode potentials
Problem
A galvanic cell employs a lead electrode in 1.0 M Pb(NO₃)₂ and a silver electrode in 1.0 M AgNO₃ connected by a KNO₃ salt bridge. After current has flowed for some time, white crystals have grown on the silver electrode, the lead electrode has become smaller, and the mass of the salt bridge near the lead half-cell has increased. Which statement about ion movement through the salt bridge is most consistent with these observations?
(a) K⁺ ions migrate toward the lead half-cell to balance the increasing Pb²⁺ concentration.
(b) NO₃⁻ ions migrate toward the silver half-cell to balance the decreasing Ag⁺ concentration.
(c) NO₃⁻ ions migrate toward the lead half-cell to balance the increasing Pb²⁺ concentration.
(d) The salt bridge has no net ion migration; electrons moving through the wire supply the necessary charge balance.