A salt bridge contains `"_____"` and agar-agar.
(i) a statured solution fo ` HCl`
(ii) A saturated solution fo `KNO_3`
(iii) a saturated solution of ` NH_4NO_3`.

Options

A. (i), (ii), (iii)
B. (i), (ii)
C. (ii), (iii)
D. (iii) only

Answer

A

Explanation

To complete the electric circuit of a galvanic cell, the solutions must be connected by a conducting medium through the cations and anions can move. This requirement is satisfied by a salt bridge, which in its simplest form is an inverted U tube containing an inert electrolyte such as ` KCl, KNO_3,` or `NH_4NO_3`, whose ions will not react with the other ions in solution or with the electrodes. During the course of the overall redox reaction, electrons flow extrenally from the anode through the wire and voltmeter to the cathode . In the solution, the cation move toward the cathode, while the anions move in the opposite dirction, toward the anode .