Question

In the preparation of chlorine by the electrolysis of brine, the reaction taking place at the anode is

• A. $Cl ^{-}(a q) \longrightarrow \frac{1}{2} Cl _{2}(g)+e^{-}$
• B. $Na ^{+}(a q)+e^{-} \longrightarrow Na ( s )$
• C. $O _{2}( g )+4 H ^{+}+4 e ^{-} \longrightarrow 4 H _{2} O (I)$
• D. $H ^{+}(a q)+ e ^{-} \longrightarrow \frac{1}{2} H _{2}(g)$

Answer 1

Answer: (A)

Chlorine can be manufactured by electrolysis of a sodium chloride solution (brine). The production of chlorine results in the co-products of caustic soda (sodium hydroxide, $NaOH$ ) and hydrogen gas $\left( H _{2}\right)$.

At cathode $2 H ^{+}(a q)+2 e^{-} \longrightarrow H _{2}(g)$

At anode $Cl ^{-}(a q) \longrightarrow \frac{ l }{2} Cl _{2}(a q)+e^{-}$

or $2 Cl ^{-}(a q) \longrightarrow Cl _{2}(g)+2 e^{-}$