In conjunction with a standard hydrogen electrode, the La3+|La half-cell is the anode and the standard cell potential is 2.52V. What is the standard reduction potential for the La3+|La half-cell?
If the La3+/La electrode is the anode, that means the reaction at that electrode is
La ==> La^+3 + 3e (remember that oxidations occurs at the anode) and the cell potential is +2.52 v. So the standard reduction reaction is La^+3 + 3e ==> La and the potential is -2.52 v.
To determine the standard reduction potential for the La3+|La half-cell, we need to use the Nernst equation:
Ecell = E°cell - (0.0592 / n)log(Q)
Where:
Ecell is the standard cell potential (2.52V),
E°cell is the standard reduction potential for the half-cell we are interested in (La3+|La),
n is the number of electrons involved in the half-cell reaction, and
Q is the reaction quotient (which is equal to 1 when concentrations of all species are 1M).
Since the half-cell is the anode, the standard reduction potential for the La3+|La half-cell will be the negative value of the standard cell potential:
E°cell = -2.52V
Plugging in the values, we get:
-2.52V = E°cell - (0.0592 / n)log(1)
Since log(1) equals 0, we can simplify the equation to:
-2.52V = E°cell
Therefore, the standard reduction potential for the La3+|La half-cell is -2.52V.
To determine the standard reduction potential for the La3+|La half-cell, you can utilize the standard cell potential and the standard reduction potential of the standard hydrogen electrode (SHE).
The standard cell potential (E°cell) is the difference in standard reduction potentials between the two half-cells. In this case, the half-cell at the anode (La3+|La) is being compared to the half-cell at the cathode (standard hydrogen electrode).
The standard reduction potential of the standard hydrogen electrode is defined as 0.00V by convention. This means that it acts as the reference point for measuring the reduction potentials of other half-cells.
Therefore, to determine the standard reduction potential for the La3+|La half-cell, you need to subtract the standard potential of the standard hydrogen electrode (0.00V) from the standard cell potential (2.52V):
E°cell = E°cathode - E°anode
2.52V = 0.00V - E°anode
E°anode = 0.00V - 2.52V
E°anode = -2.52V
Hence, the standard reduction potential for the La3+|La half-cell is approximately -2.52V.