Q. Which one of the following reactions occur at the anode, in the Castner process of extracting sodium metal?
A) $H_{2}\ \rightarrow 2H^{+} + 2e^{-}$
B) $2{Cl}^{-}\ \rightarrow {Cl}_{2} + 2e^{-}$
C) $4{OH}^{-}\ \rightarrow 2H_{2}O + O_{2} + 4e^{-}$
D) ${Na}^{+} + e^{-}\ \rightarrow Na$
Explanation
(c)
In Castner process the process of extracting sodium metal can be written as,
$\ \ \ \ \ \ \ \ \ \ 4NaOH\ \longrightarrow 4Na^{+} + 4OH^{-}$
Its oxidation reaction which occurs at anode is
$\ \ \ \ \ \ \ \ \ \ \ \ \ \ 4OH^{-} \longrightarrow 2H_{2}O + O_{2} + 4e^{-}$
Reviewed by Dr. Abubacker
Physics Educator & NEET/JEE Specialist
Ph.D. in Physics with 19+ years of teaching experience.