Question

In the extraction of chlorine by electrolysis of brine ____________.

• A. reduction of $C{l}^{-}$ ion to chlorine gas occurs..
• B. For overall reaction $\Delta G^{\Theta }$ has negative value.
• C. oxidation of $C{l}^{-}$ ion to chlorine gas occurs.
• D. a displacement reaction takes place.

Answer 1

The correct option is C oxidation of $C{l}^{-}$ ion to chlorine gas occurs.

Option (a):

Chlorine can be manufactured by the electrolysis of a sodium chloride solution (brine), which is known as the Chlor-Alkali process.

Here oxidation state of chlorine is increasing from -1 to 0 (hence oxidation takes place).


So, option (a) is correct

Option (b):

There should always be oxidation of $C{l}^{-}$ ion to chlorine gas, because here the oxidation state of $Cl$ is increasing from -1 to 0.

Option (c):


The $\Delta G^{\Theta }$ for this reaction is $+422kj$ i.e., positive.

Option (d):

In electroiysis reactions oxidation-reduction occurs.

Overall process:


This is not displacement reaction.

Hence option (a) is correct