Question

Problem 20.26
A voltaic cell similar to that shown in Figure 20.5 in the textbook is constructed. One electrode compartment consists of an aluminum strip placed in a solution of Al(NO3)3, and the other has a nickel strip placed in a solution of NiSO4. The overall cell reaction is
2Al(s)+3Ni2+(aq)→2Al3+(aq)+3Ni(s)
Part A
What is being oxidized?
Express your answer as a chemical expression.

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Part B
What is being reduced?
Express your answer as a chemical expression.

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Part C
Write the half-reactions that occur in the two electrode compartments.
Express your answer as a chemical equation. Identify all of the phases in your answer.

anode reaction:
3Ni2++6e−→3Ni

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Part D
Express your answer as a chemical equation. Identify all of the phases in your answer.

cathode reaction:

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Part E
Which electrode is the anode, and which is the cathode?

Which electrode is the anode, and which is the cathode?

Al electrode is the anode, Ni electrode is the cathode.
Ni electrode is the anode, Al electrode is the cathode.

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Part F
Indicate the signs of the electrodes.

Indicate the signs of the electrodes.

Ni electrode is negative, Al electrode is positive.
Al electrode is negative, Ni electrode is positive.

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Part G
Do electrons flow from the aluminum electrode to the nickel electrode, or from the nickel to the aluminum?

Do electrons flow from the aluminum electrode to the nickel electrode, or from the nickel to the aluminum?

Electrons flow from the aluminum electrode to the nickel electrode.
Electrons flow from the nickel electrode to the aluminum electrode.

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Part H
In which directions do the cations and anions migrate through the solution? Assume the Al is not coated with its oxide.

In which directions do the cations and anions migrate through the solution? Assume the  is not coated with its oxide.

Cations migrate to the nickel electrode, anions migrate to the aluminum electrode.
Cations and anions migrate to the aluminum electrode.
Cations and anions migrate to the nickel electrode.
Cations migrate to the aluminum electrode, anions migrate to the nickel electrode.

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Answer 1

A)

The reaction:

2Al(s)+3Ni2+(aq)?2Al3+(aq)+3Ni(s)

recall that Oxidation = species loses electrons

from the reaction Al goes from 0 in Al(s) to +3 in Al+3(aq), therefore,

Aluminium is being oxidzied;

B) reduction is gain in electrons,

Nickel goes from Ni+2 to Nickel 0, that is, gains 2 electrons;

it is being reduced;

C & D)

half reaction in both electrodes:

cathode ( reduction ) Ni+2(aq) + 2e- --> Ni(s)

anode (oxidation) Al(s)--> Al+3(aq) + 3e- D) Total reaction is

E)

ANODE = electrons donation, which is Al(s)

CATHODE = reception of electrons, which is Ni+2(aq)

F)

cathode is reduction, will receive electrons, so it is +

anode is oxidation, will it donate electrons, it is -

G)

Do electrons flow from the aluminum electrode to the nickel electrode, or from the nickel to the aluminum?

Electrons flow from Solid Al(s) to the Nickel electrode in Ni2+

H)

The cation will balance current so

cations (+ charge) go to the anode

anions ( -charge) go to the cathode