What happens in the extraction of chlorine by electrolysis of brine?

1. Oxidation of $C{l}^{-}$ ion to chlorine gas occurs.

2. Reduction of $C{l}^{-}$ ion to chlorine gas occurs.

3. For overall reaction has negative value.

4. A displacement reaction takes place.

HINT: Oxidation of $C{l}^{-}$ ion to chlorine gas occurs.
Explanation:
Following reaction takes place in the extraction of chlorine by electrolysis :
From the above reaction it is very clear that the oxidation of $C{l}^{-}$ ion to chlorine gas occurs. Thus, option (1) is the correct answer.
$∆G°$ for this reaction is +422kJ. Therefore, thermodynamically reaction is not feasible.
We know that ,
$∆°G=-nFE°$
By using this equation value of $E°$ can be calculated. Thus,
$E°=-\frac{∆G°}{nF}=-2.2V$
Therefore, for the occurrence of this reaction, external potential (emf) greater than 2.2V is required . Due to this fact (3) is not the correct option.