Question

What exactly is ELECTRODE POTENTIAL ?? in electrochemistry----------------------

Answer 1

according to my knowledge ,it is the potential difference between the electrode and the electrolyte,,,,,,but again ,what is REDUCTION potential, and OXIDATION potential??? i guess these terms cant be explained in a normal "PHYSICS" potential.......please help!!

Answer 2

this ought to be in CHEM,, but i wanted an explanation in terms of "electric potential ".......please help me out!

Answer 3

http://www.physicsclassroom.com/Class/circuits/u9l1b.cfm This really clarified for me...

Answer 4

THAT REALLY helped!! thanks!

Answer 5

My pleasure! Very glad I could help.

Answer 6

hey! just one more doubt........u know electrons travel throughout the circuit,,,they start at the -ve electrode,, go thru the copper wire(circuit) and end up in the +ve electrode.....now inside the cell,, these electrons need to be carried from the +ve electrode to -ve electrode so that they can cycle again,,,,,,BUT these electrons are strongly attracted to the +ve electrode,,,how do they even move towards the -ve electrode,,,,they also face another problem : repulsion from the -ve electrode,,,,,then how do they accomplish the movement ??

Answer 7

@CliffSedge

Answer 8

The electrons don't actually cycle around. It is the net drift of electric charge, not the particles themselves.

Answer 9

Also you need to be careful about what convention you are using to name an electrode as positive or electrode. A cathode (positive electrode) is a source of electrons, etc.

Answer 10

ohk!

Answer 11

so inside the cell ,, the cations are in motion right??

Answer 12

then in that case,,,for reduction to happen, they said the cations must move towards the cathode(+ve electrode),,,so that they get reduced.....but dont cations get repelled from he +ve electrode?

Answer 13

*the

Answer 14

Depends on the cell. Electric current can either be due to moving positive charges or moving negative charges. For electricity flowing through metal wires, it is the negatively charged electrons that are moving (though, by convention, the opposite direction flow of positive charge is still considered the direction of current).
Positively charged cations can flow through an electrolyte and they will move from anode to cathode.

Answer 15

ok! but what about the repulsion thing?

Answer 16

Check your sign convention.
Cathodes are positive because they either release / emit electrons (-ve charge) or because they are accumulating cations (+ve charge).

Answer 17

again im confused! so according to u "either emitting electrons (-ve charge) or accumulating cations (+ve charge). " is one and the same....? But i feel both have opposite effects.......releasing electrons make it -vely charged,,whereas accumulating +ve charge makes it +vely charged!

Answer 18

by realeasing electrons i thought that.....the electrons that were sent to the cathode accumulates at the cathode end

Answer 19

They aren't identical, but they have equivalent effects. If something (a cathode) is emitting electrons, then it is losing negative charge so is left with a net positive charge. If the cathode instead attracts cations, then it is gaining positive charge. Either way, it is more positive than it was previously.

Answer 20

Electrons are not sent to cathodes. Cathodes emit/release electrons.

Answer 21

Cat-ions are positive because they have fewer electrons than neutral atoms. Cat-hodes are positive because they lost electrons or gained protons(cations)

Answer 22

ok! but in most of the videos that i watched ,,show that the electrons cant escape the cathode,,,,, they will be used up only when a cation approaches for reducing itself!

Answer 23

Hmm, are you talking about forced electrolysis?

Answer 24

no no ....galvanic cell

Answer 25

Ah, then make sure you don't confuse cathodes and anodes with positive and negative terminals.

Answer 26

when i said electrons are sent to the cathode i meant --"WHEN the electrons that cycle in the circuit arrive at the cathode end,,,,they cant escape any furthur,,unless reduction takes place"

Answer 27

no problem....cathode + anode -

Answer 28

That's the part I don't understand. What do you mean by "electrons sent to the cathode?" Cathodes emit electrons, they don't accept them.

Answer 29

If you're talking about within the cell, the electrons don't flow within the cell - it's not like water flowing through a pipe/pump (though that is a common metaphor)

Answer 30

The oppositely charged terminals generate an electric field. Electric potential difference is like a difference in air pressure that causes air to flow from high pressure to low pressure.

Answer 31

The visualization of electrons cycling around in circles is incorrect.

Answer 32

no ..wait see this ,,,,,i said about electrons being sent to the cathode.......this video shows it
http://www.youtube.com/watch?v=C26pH8kC_Wk

Answer 33

the electrons travel from the anode to the bulb,and then sent to the cathode!

Answer 34

cathode cant emit the electrons unless they accumulate them,,, and they cant accumulate them unless electrons are sent to them,,,,

Answer 35

thats waht video shows...but im not sure!

Answer 36

Oh, I see what you mean: The cathode is maintaining a positive charge because it is transferring electrons to the copper ions. The copper is being reduced.

Answer 37

The zinc is what's known as a "sacrificial anode" - it is being oxidized (having electrons stolen from it) The anode accepts electrons from the electrolyte. The cathode release electrons into the electrolyte, which are taken by the copper ions. The solution of Cl- and Na+ keep the electrolyte fueled with charges to move around.

Answer 38

i see this in 2 ways,,,and thats exactly what confuses me,,,,,,
1) in one way,,,the electrons are arriving at the cathode and are accumulated at the cathode,,,this shows cathode is -ve ly charged....another proof for the -ve charge , is that the +vely charged copper cations get attracted to the cathode,,,,,,so i feel cathode is -vely charged
2) next,,,,since the copper cations get reduced on cathodes surface, so they use up the electrons on the cathode,,,,thus cathode loses electrons for the sake of copper's(cation) reduction....since they lost electrons,, they are +vely charged.........another proof for +ve charge is that current (here) flows from cathode to anode(i mean the external circuit that includes the bulb).....now since current always flows from +ve terminal to -ve terminal ,,,
we conclude that cathode is +VE,

Answer 39

The +ve charged copper cations are not attracted to the cathode, the cathode is +ve charged because it is made out of +vely charged copper ions.

Answer 40

The copper *is* the cathode.

Answer 41

The zinc *is* the anode.

Answer 42

cathode is made out of copper metal.....not ions......the video clearly shows copper ions being attracted to the cathode!

Answer 43

and once the copper ions come in contact with the cathode,, they get reduced ,,,and u have still more copper metal on cathodes surface

Answer 44

Besides the confusing thing I said "the cathode is made out of +ve copper cations" when I meant "the cathode attracts +ve copper cations" we seem to be saying the same thing.

Answer 45

ohk!