Question

what is salt bridge in chemistry
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Answer 1

A salt bridge, in electrochemistry, is a laboratory device used to connect the oxidation and reduction half-cells of a galvanic cell (voltaic cell), a type of electrochemical cell. It maintains electrical neutrality within the internal circuit, preventing the cell from rapidly running its reaction to equilibrium. If no salt bridge were present, the solution in one half cell would accumulate negative charge and the solution in the other half cell would accumulate positive charge as the reaction proceeded, quickly preventing further reaction, and hence production of electricity.[1]

Answer 2

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$\longrightarrow$ A commonly used form of salt bridge consists of a glass U- tube containing semi- solid paste of either KCl, $KNO_3$ or $NH_4Cl$ in gelatin or agar-agar jelly.

$\longrightarrow$ The electrolytes that are often used in salt bridge are called inert electrolytes which are supposed:

not to interact chemically weather of the solutions present in a anodic or cathodic Chambers.

not to interfere with overall cell reaction.

only those electrolytes can be used in a Salt Bridge in which mobility of Ions is almost the same.

Example, KCl, $K_2SO_4$, etc.

$\longrightarrow$ A salt bridge carries out two important functions:

It allows only flow of Ions through it. Thus, the circuit is completed.

It also maintains the electrical neutrality.