Electrolytic Reactions: Anode vs Cathode

In summary, the electrolyte is a good conductor of ions, not electrons, so the electrons will only move from the plates with a good conductor of electrons (wire) connected to the plate +- terminals.
  • #1
shivaniits
39
0
hey guys
i have put this question to clarify some points on battery anode cathode reactions...let me describe this..if we consider the cell to be two electrodes with in between electrolyte ..
at anode one has the situation:
metal=metal ion+electron released
i.e oxidation takes place..!
so why can't these electrons go directly to other electrode through electrolyte and it would be a shorter path too..i am literally confused about a point that if two electrodes are immersed in same electrolyte...which is an excellent conductor should not lead to short circuit and carry the electrons from directly through a shorter path rather than going through the whole circuit..??
 
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  • #2


Electrons can't through the electrolyte - ions can.

In some solvents (like ammonia) solvated electrons are relatively stable, so probably battery made with liquid ammonia would behave slightly differently.
 
  • #3


hi there
ok so electrons can not go though but ions can..is this all happening due to the formation of DL(double layer) that acts as an insulator between electrode and electrolyte..!
http://en.wikipedia.org/wiki/Helmholtz_double_layer
 
  • #4


No, double layer has nothing to do with the situation.
 
  • #5


Borek said:
No, double layer has nothing to do with the situation.

ok so what it is that's preventing the movement of electrons in electrolyte but yet allows the movement of ions..??
why we observe this kind of behavior..!
 
  • #6


Electrons are not stable in the solution, they react with water.

Besides, why should they even try to go through the solution if they can go through an external circuit, which has much lower resistance?
 
  • #7


Borek said:
Besides, why should they even try to go through the solution if
they can go through an external circuit, which has much lower resistance?

that's because electrolyte is a good conductor..and if the attached load is of mega ohms or
an other higher value..won't the electrolyte would provide the shorter path between the terminals...!
won't the electrons prefer the shorter path instead of going a way long from one electrode to other..!
besides that one can't completely ignore the fact of electrolyte being conductive..!
 
  • #8


Electrolyte is not as good conductor as you seem to be thinking, plus - as stated earlier - electrons in the solution would react with water molecules.
 
  • #9


shivaniits said:
that's because electrolyte is a good conductor..and if the attached load is of mega ohms or
an other higher value..won't the electrolyte would provide the shorter path between the terminals...!
won't the electrons prefer the shorter path instead of going a way long from one electrode to other..!
besides that one can't completely ignore the fact of electrolyte being conductive..!

The electrolyte is a good conductor of ions not electrons so the electrons will only move from the plates with a good conductor of electrons (wire) connected to the plate +- terminals.
http://www.av8n.com/physics/lead-acid.htm

One way to look at this starts by observing that the electrochemical potential is a potential i.e. the energy of the bisulfate ion is a function of position, independent of how the ion got to that position.

The height of this potential can be considered a “barrier” to the reaction.

In equilibrium, i.e. when the cell is open-circuited, the electrochemical potential is everywhere an equipotential, i.e. the height is independent of position. The mystery arises when I place the cell under load. This manifestly shifts the potential. The terminal marked "+" will become less positive, i.e. more negative, becoming unattractive to negatively-charged ions. We can calculate the density of ions using the Boltzmann factor, ρ ∝ exp(−E / kT).

This can be called the "static" or "integral" view of the situation.
 
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  • #10


Borek said:
No, double layer has nothing to do with the situation.

I am not so sure about that. The double layer guarantees that the interior of the solution is field free. So an electron in the solution would not experience any driving force.
 
  • #11


DrDu said:
I am not so sure about that. The double layer guarantees that the interior of the solution is field free. So an electron in the solution would not experience any driving force.

Same about ions, yet they move.

But I agree I overdid with the answer. What I really meant was that you can answer the question without invoking the double layer.
 
  • #12


nsaspook said:
The electrolyte is a good conductor of ions not electrons so the electrons will only move from the plates with a good conductor of electrons (wire) connected to the plate +- terminals.
i agree with fact that something being stated as conductor is one that responds to electric field with its own charges..as ions in case of electrolyte and in case of solids in which tere are no free ions the electrons serve as charges for conduction...!
but i am here concerned about the point that if they something is at different potential..within a medium which is rather conductive they are most probable chances of getting them discharged producing static electricity..due to imbalance of charges at different electrodes and since electrolyte is conductive though conducts with help of free ions...they can discharge ..!
but if we take action of double layer it solves a little bit and i am not considering here conduction through electrons in electrolyte rather referring conduction through ions in electrolyte..!the double layer makes the rest of electrolyte unaffected by potential hence when is not in circuit the electrodes are at different potentials but can't discharge unless we provide a path...through interconnecting them in a circuit..!
 
  • #13


Basically what you wrote is "double layer makes the solution non conducting, so when we close the circuit current flows from the electrode to electrode". Well, if the solution is not conductive, circuit is not closed, so the current doesn't flow. To close the circuit you need the conductivity of the solution.
 
  • #14


Borek said:
Basically what you wrote is "double layer makes the solution non conducting
no what i actually wanted to refer is that double layer helps or actually shields the electrodes allowing the discharge only through connecting wires..!
although it doesn't allows passage of electrons but still because of ions it is still conductive..!

so on the overall this dl thing helps to understand a little bit but what if we have to look though another perspective..!
 

What is an electrolytic reaction?

An electrolytic reaction is a chemical reaction that occurs when an electric current is passed through an electrolyte solution. The electrolyte solution contains ions that can be oxidized or reduced at the electrodes, resulting in the transfer of electrons and the formation of new chemical compounds.

What is the difference between anode and cathode in electrolytic reactions?

Anode and cathode are the two electrodes used in an electrolytic reaction. The anode is the positively charged electrode where oxidation occurs, while the cathode is the negatively charged electrode where reduction occurs. This means that the anode releases electrons into the solution, while the cathode accepts electrons from the solution.

How do anode and cathode affect the direction of the electric current?

The direction of the electric current in an electrolytic reaction is determined by the movement of ions towards the electrodes. At the anode, positive ions are attracted and at the cathode, negative ions are attracted. This results in a flow of electrons from the anode to the cathode, creating an electric current.

What is the purpose of an external power source in an electrolytic reaction?

The external power source, such as a battery or power supply, is used to provide the necessary energy to drive the electrolytic reaction. The electric current from the power source supplies the energy needed to break apart the chemical bonds in the electrolyte solution and facilitate the transfer of electrons between the anode and cathode.

Can anode and cathode be reversed in an electrolytic reaction?

No, the anode and cathode cannot be reversed in an electrolytic reaction. This is because the direction of the electric current and the movement of ions are dependent on the polarity of the electrodes. Reversing the anode and cathode would result in the opposite reaction taking place, leading to a different chemical product being formed.

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