CHEMISTRY COMMUNITY

What exactly do salt bridges do? I'm sort of struggling with this concept. Thank you!

A salt bridge allows for ion transfer between the two solutions, and this allows for the two solutions to stay neutral.

Without a salt bridge to manage the unequal charges, the electrons flowing to the cathode will eventually stop because the buildup will cause electron-electron repulsion. Likewise, the anode would have such a high positive charge that it will want to hold on to the negative electrons.

salt bridges are designed to make a complete electrical circuit. Without the salt bridges, as anode keeps losing e-, it becomes less negative, and as cathode keeps accepting e-, it becomes less positive; after a period of time, anode and cathode go to equilibrium and become neutral where no e- will be transferred since the potential difference would be 0 at equilibrium. As a result, salt bridges provide negative ions to anode to keep it negative and provide positive ions to cathode to keep it positive. Hope it helps!

A salt bridge serves to keep the charges between the two solutions to remain neutral and for the redox reaction to continue.

As the e- current transfers from the anode to the cathode, the ion in the anode loses the e- to the cathode making the anode gradually positive and the cathode gradually negative. Because of this, the cell will gradually stop receiving e- from the anode because it was already negative. The salt bridge allows the transfer of other ions such as Cl- to the anode so that it keeps the charges on each side balanced. As Cl- moves to the anode, it balances out the positive charge of the anode as the e- moves to the cathode.

In the anode, electrons are taken away to be put in the cathode. This makes the anode solution more positive and the cathode solution more negative. Since electrons are also negative, if the negativity of the cathode builds up, then it would start rejecting the electrons (negatives repulse negatives). The salt bridge helps in this case. It transfers negative ions like Cl- from the cathode solution to the anode solution to balance out the change in charge.
There are also diagrams where the salt bridge gives the cathode positive ions like Na+ and gives the anode negative ions like Cl-, is this how salt bridges work? (Because in lecture, the diagram of the battery was always drawn with the salt bridge transferring negative ions from the cathode to the anode.)

does a porous disk and salt bridge have the same purpose?

A salt bridge is a connection of between the oxidation and reduction half-cells of a galvanic cell. It maintains electrical neutrality within the internal circuit, preventing the cell from rapidly running its reaction to equilibrium. In other words, only if a salt bridge is present, electricity can be produced in the galvanic cell.

Hope this helps! Have a good weekend!

How would the charges of each side be balanced using a porous disk? Also, a single line in the shorthand equation serves as a porous disk too instead of two lines signifying a salt bridge, and when the reactants and products of one half equation are in the same state you separate them by a comma.

In a battery, like a AAA battery, what serves as a salt bridge?

Salt bridges are used to transfer electrons that have already passed from the anode, to the cathode, back to the anode. This maintains equilibrium in the battery and allows it to not “die” as fast.

The salt bridge keeps the two solutions neutral so that the redox reaction can continue.

Salt bridges keep both solutions neutral as reduction and oxidation are occurring

Salt bridges allow electron transfer between two solutions.