Galvanic Cell Salt Bridge (1 Viewer)

[jackc91]

Hey I'm a little confused as to what happens with the ions in the salt bridge.

<?xml:namespace prefix = v ns = "urn:schemas-microsoft-com:vml" /><v:shapetype id=_x0000_t75 stroked="f" filled="f" path="m@4@5l@4@11@9@11@9@5xe" o:>Using the attachment as an example what actually happens to the NO3- and the K+. Is there a formation of zinc nitrate and potassium sulfate.</v:shapetype>

 

[xiao1985]

I couldn't download the attachment, but I got an idea what it looks like.

Yes, you'll start to get more and more zinc nitrate and potassium sulfate in each of the half cells (in solution form however, so you'll get Zn2+, NO3 -, K+ and SO4 2-)

In actual reality reality, charge neutrality needs to be kept. So which ever side was oxidised will have a net "positive" charge (since it lost elecron(s)), so NO3 - in the salt bridge moves in to keep the charge neutral over all.

Same can be said for the side which reduction happens.

 

[jackc91]

Ahh so the salt bridge also keeps neutral charge in the half cells. Thankyou.

 

[Rachaek]

yeah, basically how I understand it is that the electron move around the external circuit from one cell to the other. Since all the electrons are moving to one cell, this cell becomes negatively charged, and the other positive. The ions in the solution then move to counteract this buildup of charge, the positive ions being attracted to the negative cell and vice versa.

If the ions weren't able to move through, no current would flow because as soon the electrons moved to one cell, the other cell would become positive and attract all the electrons back.

Hope this makes sense and didn't confuse you more =)

 

[sinophile]

also, the salt bridge must contain ions which will not react with either of the half-cell electrolytes. The purpose of the salt bridge is to allow equilibrium of charge between the two half-cells without actualy reacting with the shit inside the cell.