Using standard reduction potentials, calculate the standard E¡Æcell, emf, for each of the following reactions. State if each reaction is spontaneous or nonspontaneous. (Use the below reactions AS WRITTEN, DO NOT REARRANGE ANY REACTIONS.) You must show the two half-reactions and balance the gain and loss of electrons.
a. H2(g) + I2(s) -> 2H^1+(aq) + 2I^1-(aq)
b. Ni^2+(aq) + 2Ce^5+(aq) -> Ni¡Æ(s) + 2Ce^4+(aq)
c. 4Ce^3+(aq) -> Ce¡Æ(s) + 3Ce^4+(aq) (Acid solution)
d. 2Al^3+(aq) + 3Cd(s) -> 2Al(s) + 3Cd^2+(aq)
Anna, I'll try again--essentially a repost of my response to your earlier electrochemical problem. I don't know the symbolism. You have an Ejcell followed by a combination of two letters (AE). What are those supposed to mean? Without some explanation, you are not likely to get any help on this board on these questions. I don't have a clue.
Using standard reduction potentials, calculate the standard Ecell, emf, for each of the following reactions. State if each reaction is spontaneous or nonspontaneous. (Use the below reactions AS WRITTEN, DO NOT REARRANGE ANY REACTIONS.) You must show the two half-reactions and balance the gain and loss of electrons.
a. H2(g) + I2(s) -> 2H^1+(aq) + 2I^1-(aq)
b. Ni^2+(aq) + 2Ce^5+(aq) -> Ni(s) + 2Ce^4+(aq)
c. 4Ce^3+(aq) -> Ce(s) + 3Ce^4+(aq) (Acid solution)
d. 2Al^3+(aq) + 3Cd(s) -> 2Al(s) + 3Cd^2+(aq)
I am sorry I just deleted the symbolism.
See my response to your later post above.
To calculate the standard cell potential (E°cell) for each of the given reactions, you need to apply the following steps:
Step 1: Identify the Half-Reactions:
Start by breaking down each overall reaction into two half-reactions: the oxidation half-reaction (where oxidation occurs) and the reduction half-reaction (where reduction occurs). This allows us to balance the gain and loss of electrons.
Step 2: Assign Standard Reduction Potentials:
Next, assign the standard reduction potentials (E°red) to each half-reaction. You can find standard reduction potentials in reference tables or textbooks.
Step 3: Determine the Overall Cell Potential:
The overall cell potential (E°cell) is obtained by taking the difference between the reduction potentials of the half-reactions (E°red(cathode) - E°red(anode)). This difference will indicate whether the reaction is spontaneous (positive E°cell) or non-spontaneous (negative E°cell).
Let's apply these steps to the given reactions:
a. H2(g) + I2(s) -> 2H+(aq) + 2I-(aq)
Oxidation Half-Reaction: H2(g) -> 2H+(aq) + 2e-
Reduction Half-Reaction: I2(s) + 2e- -> 2I-(aq)
Now, we need to assign the standard reduction potentials:
The standard reduction potential for the H+/H2 couple (from reference tables) is 0 V.
The standard reduction potential for the I-/I2 couple (from reference tables) is +0.54 V.
Next, we determine the overall cell potential:
E°cell = E°red(cathode) - E°red(anode)
E°cell = (+0.54 V) - (0 V) = +0.54 V
Therefore, the standard E°cell for reaction a is +0.54 V, indicating it is spontaneous.
b. Ni2+(aq) + 2Ce5+(aq) -> Ni(s) + 2Ce4+(aq)
Oxidation Half-Reaction: Ce5+(aq) -> Ce4+(aq) + e-
Reduction Half-Reaction: Ni2+(aq) + 2e- -> Ni(s)
The standard reduction potential for the Ce4+/Ce5+ couple (from tables) is +1.61 V.
The standard reduction potential for the Ni2+/Ni couple (from tables) is -0.25 V.
E°cell = E°red(cathode) - E°red(anode)
E°cell = (-0.25 V) - (+1.61 V) = -1.86 V
Therefore, the standard E°cell for reaction b is -1.86 V, indicating it is non-spontaneous.
c. 4Ce3+(aq) -> Ce(s) + 3Ce4+(aq) (Acid solution)
Oxidation Half-Reaction: Ce3+(aq) -> Ce4+(aq) + e-
Reduction Half-Reaction: Ce4+(aq) + e- -> Ce(s)
The standard reduction potential for the Ce4+/Ce3+ couple (from tables) is +1.61 V.
E°cell = E°red(cathode) - E°red(anode)
E°cell = (+1.61 V) - (0 V) = +1.61 V
Therefore, the standard E°cell for reaction c is +1.61 V, indicating it is spontaneous.
d. 2Al3+(aq) + 3Cd(s) -> 2Al(s) + 3Cd2+(aq)
Oxidation Half-Reaction: Cd(s) -> Cd2+(aq) + 2e-
Reduction Half-Reaction: Al3+(aq) + 3e- -> Al(s)
The standard reduction potential for the Cd2+/Cd couple (from tables) is -0.40 V.
The standard reduction potential for the Al3+/Al couple (from tables) is -1.66 V.
E°cell = E°red(cathode) - E°red(anode)
E°cell = (-1.66 V) - (-0.40 V) = -1.26 V
Therefore, the standard E°cell for reaction d is -1.26 V, indicating it is non-spontaneous.