In Castner-Kellner's process, a brine solution is electrolyzed.Which of the following is obtained at the cathode ?

Options

A. Na(Hg)
B. NaOH
C. `H_(2)(g)`
D. All of these

Answer

D

Explanation

Sodium metal discharged at the cathode (since the on the mercury) combines withh mercury to form sodium amalgam:
Cathode: `Na^(+)+e^(-)overset(Hg)toNa(Hg)`
the amalgam is treated with water to give sodium hydroxide and hydrogen gas:
`2Na(Hg)+2H_(2)Oto2NaOH+2Hg+H_(2)`