A galvanic cell is composed of two hydrogen electrodes, of which one is a standard one. In which of the following solution should the other electrode be immersed to get maximum emf

0.1 M CH₃COOH

If the correct answer is (2) 0.1 M CH₃COOH, then immersing the other hydrogen electrode in a 0.1 M CH₃COOH (acetic acid) solution will provide the maximum emf in the galvanic cell.

Acetic acid is a weak acid that partially dissociates in water, releasing a smaller concentration of H+ ions compared to strong acids like HCl. However, in this specific scenario, the standard hydrogen electrode is being used as a reference electrode. It provides a constant and known H+ ion concentration. Therefore, in order to maximize the emf, the other electrode should be immersed in a solution with a lower concentration of H⁺ ions to create a larger potential difference.

Since CH₃COOH is a weak acid, it will provide a lower concentration of H⁺ ions compared to strong acids like HCl. Thus, option (2) 0.1 M CH₃COOH is the correct answer if the goal is to maximize the emf in the galvanic cell.