Question #6bb1b
1 Answer
A salt bridge is an inverted U-tube that contains an electrolyte and connects the two half-cells in a galvanic cell.
Explanation:
The salt bridge maintains electrical neutrality in the internal circuit.
See Why do galvanic cells need a salt bridge?
Consider the galvanic cell shown below.
If there were no salt bridge, an excess of positive charge (
The
The flow of electrons through the wire would soon come to a halt
.
The salt bridge keeps the contents of each half-cell separate and allows the flow of ions to maintain a balance of charge between them.
As positive charge builds up in the left hand cell,
As negative charge builds up in the right hand cell,
Cations are flowing in one direction, and anions are flowing in the opposite direction. This countercurrent flow of ions is the internal circuit.
The process continues until the system reaches equilibrium.
Instead of a salt bridge, you can use a porous barrier of clay or fritted glass.
Some labs use beakers joined by a fritted glass disk.