JEE Advanced 2014 · Paper 1 · Chemistry Q26

ChemistryMultiple correct+3Question 26 of 60

In a galvanic cell, the salt bridge

does not participate chemically in the cell reaction.

stops the diffusion of ions from one electrode to another.

is necessary for the occurrence of the cell reaction.

ensures mixing of the two electrolytic solutions.

Answer and worked solution

Official answer: A, C

(A) The salt bridge only carries ions to keep both half-cells electrically neutral; its ions are not consumed in the cell reaction. True.
(B) It does not stop ions moving between the compartments. Ion migration through it is exactly how it works. False.
(C) Without it (or some other ionic contact) charge builds up in each half-cell and the reaction stops at once, so it is needed for the cell reaction to continue. Taken this way the statement is true; if one argues the redox reaction could occur by direct mixing, it is not, which is why the key also accepts (A) alone.
(D) It is designed to prevent mixing of the two electrolytes. False.

(A), (C) (the key accepts A and C, or A alone)

JEE Advanced 2014 · Paper 1, Chemistry question 26