Salt Bridge - Filter Paper Bridges

Filter Paper Bridges

The other type of salt bridge consists of a filter paper, also soaked with a relatively inert electrolyte, usually potassium chloride or sodium chloride because they are chemically inert. No gelification agent is required as the filter paper provides a solid medium for conduction.

Conductivity of this kind of salt bridge depends on a number of factors: the concentration of the electrolyte solution, the texture of the filter paper and the absorbing ability of the filter paper. Generally, smoother texture and higher absorbency equates to higher conductivity.

A porous disk or other porous barrier between the two half-cells may be used instead of a salt bridge; however, they basically serve the same purpose.