given the overall cell reaction Zn(s) + 2Ag(aq) --> Zn2+ (aq) + 2 Ag(aq) which will occur when the cell operates
no question
Zn(s)-->Zn2+(aq) + 2e- (Oxidation at Anode)
2Ag2+(aq) + 2e- ---->2Ag(s) (Reduction at Cathode)
In the given cell reaction Zn(s) + 2Ag(aq) → Zn2+(aq) + 2Ag(aq), zinc is being oxidized to Zn2+(aq) while silver ions are being reduced to Ag(aq).
To determine which half-reaction occurs at the anode and which occurs at the cathode, we need to compare the standard reduction potentials (E°) of the half-reactions involved.
The half-reaction with the more negative (less positive) reduction potential will occur at the anode (oxidation) while the half-reaction with the more positive reduction potential will occur at the cathode (reduction).
Looking up the standard reduction potentials for Zn2+(aq) and Ag(aq) in a table, we find that:
- Standard reduction potential for Zn2+(aq) is -0.761 V
- Standard reduction potential for Ag(aq) is +0.799 V
Since Ag(aq) has the more positive reduction potential compared to Zn2+(aq), it will be reduced at the cathode. Therefore, the half-reaction 2Ag(aq) is reduced to Ag(aq) will occur at the cathode.
Conversely, since Zn2+(aq) has the more negative reduction potential, it will be oxidized at the anode. Therefore, the half-reaction Zn(s) is oxidized to Zn2+(aq) will occur at the anode.
Hence, the overall cell reaction Zn(s) + 2Ag(aq) → Zn2+(aq) + 2Ag(aq) will occur with zinc being oxidized at the anode and silver ions being reduced at the cathode.
To determine which reaction will occur when the cell operates, we need to compare the standard reduction potentials of the half-reactions involved. The cell reaction consists of two half-reactions: the oxidation half-reaction and the reduction half-reaction.
The oxidation half-reaction occurs at the anode, where Zn undergoes oxidation and loses electrons:
Zn(s) → Zn2+(aq) + 2e-
The reduction half-reaction occurs at the cathode, where Ag+ ions are reduced and gain electrons:
Ag+(aq) + e- → Ag(s)
To find out which reaction will occur when the cell operates, we need to compare the standard reduction potentials (E°) for each half-reaction. Standard reduction potential is a measure of the tendency of a species to gain electrons and be reduced. The reaction with the higher standard reduction potential will occur at the cathode, while the reaction with the lower standard reduction potential will occur at the anode.
Looking up the standard reduction potentials, we find that the standard reduction potential for the reduction of Ag+ ions to Ag(s) is +0.80 V, and the standard reduction potential for the oxidation of Zn to Zn2+ ions is -0.76 V. Since the reduction potential of Ag+ to Ag is higher than the oxidation potential of Zn to Zn2+, Ag+ ions will be reduced (Ag(s) will be deposited) at the cathode, and Zn will undergo oxidation at the anode.
Therefore, when the cell operates, Zn(s) will be oxidized at the anode, and Ag+(aq) will be reduced to Ag(s) at the cathode.