In the extraction of chlorine by electrolysis of brine_________.

Options

A. Oxidation of `Cl^(-)` ion to chlorine gas occure
B. Reduction of `Cl^(-)` ion to chlorine gas occurs
C. For overall reaction `Delta G^(Theta)` has negative value
D. A displacement reaction takes place

Answer

A

Explanation

Following reaction takes place in the extraction of chlorine by electrolysis
`2H_(2)O(I) + 2CI_((aq))^(-) rarr H_(2) (g) + Cl_(2)(g)+ 2OH_((aq))^(-)`
From the above reaction it is very clear that the oxidation of `Cl^(-)` ion to chlorine gas occurs. Thus, option (a) is the correct answer.
`Delta^(@)G` for this reaction is +422kJ. Therefore, thermodynamically reaction is not feasible.
We know that
`Delta G =- n FE^(@)`
By using this equation value of `E^@` can be calculated. Thus,
`E^(@) = - (Delta G^@)/(nF) = -2.2V`
Therefore, for the occurrence of this reaction, external potential (emf) greater than 2.2V is required. Due to this fact (c) is not correct option