Ncert Exercises & Solutions

Why is an external emf of more than 2.2V required for the extraction of ${Cl}_{2}$ from brine?

NEETprep Answer:

2 {Cl}^{-} (aq) + 2 H_{2} O (l) \to 2 {OH}^{-} (aq) + H_{2} (g) + {Cl}_{2} (g)

For the given reaction, value of

∆

G° is + 422 kJ,
Using

∆

G° = - nFE°, the value of E° =-2.2V,
Therefore, an external emf greater than 2.2 V is required for the extraction of

{Cl}_{2}

from brine.