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Porous disc explanation?

Posted: Wed Feb 20, 2019 5:51 pm
by Chloe Thorpe 1J
I understand the function of a salt bridge, but how does the porous disk act in the absense of the salt bridge? Is it a different setup entirely?

Re: Porous disc explanation?

Posted: Wed Feb 20, 2019 5:54 pm
by juliasloan_4g
I believe that the porous disk serves the same function as the salt bridge

Re: Porous disc explanation?

Posted: Wed Feb 20, 2019 10:47 pm
by Lia Inadomi 1I
The porous disk is between the two beakers and allows flow of electrons so that the solution that is reduced can still gain electrons and won't repel the electrons

Re: Porous disc explanation?

Posted: Wed Feb 20, 2019 10:51 pm
by Vy Lu 2B
The main difference is that the use of porous disk implies that the solutions are not in separate beakers and allows electron flow; overall the function of the porous bridge is same as that of the salt bridge: prevent charge buildup on one electrode.

Re: Porous disc explanation?

Posted: Wed Feb 20, 2019 11:28 pm
by Matthew Tran 1H
A quick correction to some of the answers: a salt bridge or porous disc allows ion transfer, not electron transfer. Electron transfer takes place along the wire (hence the electric current). In the Cu/Zn galvanic cell example, the salt bridge provides anions to the anode beaker because Zn is being oxidized (the concentration of Zn2+ ions in the beaker increases and the anions balance out the charge). Conversely, the salt bridge provides cations to the cathode beaker because Cu is being reduced (the concentration of Cu2+ ions in the beaker increases and the cations balance out the charge). If there were a porous disk instead of a salt bridge, the Zn2+ ions would move towards the cathode half of the cell and balance the charge in both halves of the cell.

Re: Porous disc explanation?

Posted: Thu Feb 21, 2019 1:04 am
by Mhun-Jeong Isaac Lee 1B
The porous disk serves essentially the same function as a salt bridge. Both allow ion transfer so that the two solutions stay neutral.

Re: Porous disc explanation?

Posted: Thu Feb 21, 2019 1:18 am
by Celio_G_Dis2C
Porous disk ~ Salt bridge: both serve the function of transferring ions