Page 1 of 1

function of a salt bridge

Posted: Tue Feb 14, 2017 2:38 am
by Julianne Seog 3K
I am still confused on how the salt bridge maintains the neutrality of the two solutions. What exactly does the salt bridge transfer, and from and to where does it transfer and it's effects?

Re: function of a salt bridge

Posted: Tue Feb 14, 2017 3:11 am
by Christina_F_3F
My understanding of a salt bridge is that it is meant to keep both solutions neutral. There is electron flow between the cathode and the anode; electrons flow from the anode, the site of oxidation, to the cathode, the site of reduction. If there was no salt bridge, as electrons were removed from the anode, the anode solution would become slightly positively charged (since electrons are leaving the anode, leaving a greater concentration of cations). In contrast, the cathode solution would become slightly negatively charged without a salt bridge because the influx of electrons from the anode would make the concentration of anions greater than that of cations. Therefore, the salt bridge allows the flow of a neutral salt (like KCl) to flow freely between the two parts of the galvanic cell to keep the solutions neutral.

I hope this helps!

Re: function of a salt bridge

Posted: Tue Feb 14, 2017 10:49 am
by Amy_Bugwadia_3I
Exactly what Christina said! Essentially, the salt bridge is to keep both solutions neutral (allows for the transfer of ions between solutions). A porous disk can also function the exact same way as a salt bridge. However, the difference is that with a porous disk, it's essentially a membrane that separates the two solutions which are contained within one container, versus with a salt bridge, there are two separate containers for the two separate solutions.