1. The balanced net ionic equation for the reaction occurring in the galvanic cell is:
Co(s) + 2Ag⁺(aq) → Co²⁺(aq) + 2Ag(s)
2. To determine which electrode is the anode, we need to compare the standard reduction potentials of the two half-reactions involved in the cell. The half-reaction with the more negative standard reduction potential will occur at the anode, while the half-reaction with the more positive standard reduction potential will occur at the cathode.
From the given reduction potentials:
Co²⁺(aq) + 2e⁻ → Co(s) E° = -0.28 V
Ag⁺(aq) + e⁻ → Ag(s) E° = +0.80 V
We see that the reduction potential for the Co²⁺/Co half-reaction is more negative than that of the Ag⁺/Ag half-reaction. This means that the Co electrode is the anode, and the Ag electrode is the cathode.
3. Yes, KCl could be substituted for KNO3 in the salt bridge. The purpose of the salt bridge is to maintain electrical neutrality in the two compartments of the cell by allowing ions to flow between them. KCl would be just as effective as KNO3 in performing this function, as both salts dissociate into cations and anions in solution.
However, the choice of salt does affect the potential of the cell, as the composition of the salt bridge can impact the rate of ion transfer between the compartments. In general, a salt bridge with a higher concentration of ions will have a lower resistance and allow for faster ion transfer, which can result in a higher cell current and a more stable cell potential.