Q) Whcih process according to Nelson's or caster - Keller  process, is  betterfor producing NAOH; Explain tha process

Ans:
Nelson's Process:- ( Perforated diaphragm Process)
Principle: In this method NaOH is manufactured by the electrolysis of brine solution using
perforated steel U-tube as cathode and a graphite rod as anode.
Na + + Cl - ( Ionization )
NaCl
H 2O
H + + OH - ( Ionization )
2 H + + 2e - → H 2 ( at cathode )
→
2 H + + 2e - ?? H 2 ( at cathode ) ?
?
? (Electrolysis)
-
-
2Cl ?? Cl2 + 2e ( at anode ) ?
→
?
Na + + ?? NaOH
→
Process :
Nelson's cel consists of a perforated steel U - tube lined inside with asbestos, which acts as
cathode. Brine solution is taken into it. The whole apparatus is suspended in an iron tank, provided
with outlets (one for H 2 and the other for Cl2 ) The tank is provided with steam arrangement. A
graphite rod suspended in the brine solution acts as anode.
The cathode and anode are connected by means of wires to the terminals of a battery and at
the same time steam is passed. Electrolysis takes place. NaOH collects into the the trough provided
at the bottom