Question

$KCl$ is used in salt bridge because:

• A. It forms a good jelly with agar-agar
• B. It is a strong electrolyte
• C. It is a good conductor of electricity
• D. Mobility of $K^{+}$ and $C{l}^{-}$ ions are almost same

Answer 1

The correct option is D Mobility of $K^{+}$ and $C{l}^{-}$ ions are almost same

Salt bridge is a U–shaped inverted tube that contains a gel (paste of agar-agar powder) permeated with an inert electrolyte (eg: $KCl$)
Salt bridge connects the cathode and anode electrode internally.

Criteria for electrolyte in a salt bridge:
1. The electrolytes should consist of cations and anions having same mobility.
2. It should not react with the ions in the solution.
3. It should not oxidised/reduced at the electrodes

$KCl$ has all these 3 criteria and is generally preferred for salt bridge.