Question

In an electro-chemical cell, the purpose of the salt bridge is:
A.to allow electron migration
B.to allow neutron migration
C.to allow ion migration
D.to prevent ion migration
E.none of these

Answer 1

A salt bridge is used to connect the oxidation and reduction of half cells of a voltaic cell or galvanic cell. The salt bridge is connected with oxidation and reduction of half cells of a galvanic cell. The oxidation occurs at anode (negative terminal) and the reduction occurs at cathode (positive terminal). The current flow from the negative terminal to the positive terminal, i.e., from anode to cathode. As a memory aid, the alphabetic order, i.e., A (anode) comes before C (cathode). The phenomenon of chemical changes taking place by the passage from an external source is called electrolysis.

Complete step by step answer:
The use of the salt bridge is to maintain the electrical neutrality within the internal circuit. It is used to prevent the cell from causing a reaction. If there is no salt bridge in the galvanic cell, then one side of the will have a positive charge and the other half will have a negative charge. But the main purpose of the salt bridge is to maintain the ionic balance. The functions of the salt bridge are it completes the electrical circuit, maintains the electrical neutrality of two half-cell solutions.
Thus, option A. is the right answer.
In an electro-chemical cell, the purpose of the salt bridge is electromigration.

Note:
The substances such as sodium chloride, potassium nitrate is generally used as an electrolyte. Also, there are two types of salt bridges, such as glass tube and filter paper bridge. The ions of the electrochemical changes do not occur. An Early example of a galvanic cell is a Daniel cell, invented by the British chemist John Daniel in 1836.