Voltaic (Daniell) Cell: Zinc Oxidation Explained

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I am only providing a summary of the conversation.In summary, the conversation was about the Daniell cell and the process of oxidation and reduction. The question raised was why the zinc electrode gets oxidized without any reason, to which the answer was that it is a spontaneous reaction. Even if only zinc is present, it will lose electrons, as seen in experiments where the zinc rod becomes thinner and shorter. It is not necessary for the copper half cell to be connected for zinc to lose electrons, as zinc has a greater oxidation potential compared to copper. This can be seen in the electrochemical series. The question was also raised about the use of half cells in redox chemistry and the reliance on the Standard Hydrogen Electrode (SHE) for
  • #1

gracy

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Me and one of my friend had a discussion about daniell cell my friend raised a doubt why does zn electrode gets oxidised without any reason?I answered her because it is spontaneous reaction.even if you will take only zinc beaker and zinc rod dipped in it zinc will lose electrons this is marked while doing experiment as zinc rod becomes thinner and shorter.so it is not that copper half cell is connected that's why zinc loses electron even without copper zinc does http://so.it/ [Broken] is to be noted that copper also loses electron when not connected with zinc but when gets connected with zinc by conducting wire zinc has greater oxidation potential as compared to copper (go through electrochemical series )so zinc wins and gets oxidized, as oxidation can not occur alone there has to be reduction so copper gets reduced .
.Am i right?
 
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  • #2
Not trying to insult you, but your posts will be much easier to read if you refrain from posting one long sentence.

I have two questions for you assuming I understood your post.

1. In your hypothetical metallic zinc bar + ZnCl2 setup, where would the electrons go?

2. If you are correct in your assumptions, it may be expected that we can simply use half cells to do redox chemistry, measure currents and so on. Why then do we have no absolute measurements of redox potentials but instead rely on something like the Standard Hydrogen Electrode (SHE) arbitrarily set to zero for our tables of standard reduction potentials?
 
  • #3
gracy said:
if you will take only zinc beaker and zinc rod dipped in it zinc will lose electrons this is marked while doing experiment as zinc rod becomes thinner and shorter.so it is not that copper half cell is connected that's why zinc loses electron even without copper zinc does http://so.it/ [Broken]
During your lab class you noticed some of the disconnected zinc rod disolved in zinc chloride solution? I doubt it. Maybe over a period of weeks some of it might.

You also saw some of the isolated copper strip dissolve away, too? Over what period of time did you observe this?
 
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  • #4
Yanick said:
Not trying to insult you
There is nothing to feel insulted.
 

1. What is a Voltaic (Daniell) Cell?

A Voltaic (Daniell) Cell is an electrochemical cell that converts chemical energy into electrical energy. It consists of two half-cells, one with a zinc electrode and zinc sulfate solution, and the other with a copper electrode and copper sulfate solution. The two half-cells are connected by a salt bridge, allowing ions to flow between them and complete the circuit.

2. How does zinc oxidize in a Voltaic (Daniell) Cell?

In a Voltaic (Daniell) Cell, zinc oxidizes by losing two electrons to the external circuit. These electrons flow through the circuit to the copper electrode, creating a flow of electrical current. The zinc ions from the zinc sulfate solution then travel through the salt bridge to the copper half-cell, where they are reduced to metallic zinc.

3. Why is zinc used as the anode in a Voltaic (Daniell) Cell?

Zinc is used as the anode in a Voltaic (Daniell) Cell because it is a highly reactive metal. This means that it readily loses electrons, making it a good source of electrons for the external circuit. Additionally, zinc is relatively inexpensive and readily available, making it a practical choice for use in commercial batteries.

4. What is the purpose of the salt bridge in a Voltaic (Daniell) Cell?

The salt bridge in a Voltaic (Daniell) Cell serves two important purposes. First, it allows for the flow of ions between the two half-cells, completing the circuit and allowing for the transfer of electrons. Second, it prevents the solutions in the two half-cells from mixing, which could lead to an imbalance of charges and an interruption in the flow of current.

5. How does the Daniell Cell demonstrate principles of electrochemistry?

The Daniell Cell demonstrates principles of electrochemistry by showing how chemical reactions can produce electrical energy. This is achieved through the oxidation and reduction reactions that occur at the anode and cathode, respectively. It also demonstrates the concept of redox reactions, where one species loses electrons (oxidation) and another gains electrons (reduction).

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