A salt bridge is a device used in an electrochemical cell for connecting its oxidation and reduction half cells wherein a weak electrolyte is used. In other words, a salt bridge is a junction that connects the anodic and cathodic compartments in a cell or electrolytic solution.
The salt bridge usually consists of a strong electrolyte which is further made up of ions. For example, AgNO3, KCl, etc. Salt bridges are generally used in a galvanic cell such as a voltaic cell or Daniel cell.
- Salt bridge prevents the diffusion or mechanical flow of solution from one-half cell to another.
- It prevents or minimizes the liquid-liquid junction potential. (Potential arises between two solutions when they are in contact with each other).
- Salt bridge acts as an electrical contact between two half cells.