In a galvanic cell, the salt bridge does not participate chemically in the cell reaction. The ions of the electrolyte present in the salt bridge neither react with the ions of the electrode solutions, neither get oxidized nor get reduced at the electrodes. The salt bridge provides electrical contact between the two solutions and thereby completes the electrical circuit. It does not ensure the mixing of electrolytes of solution. It maintains electrical neutrality in both the solutions by a flow of ions.