Question

High purity (> 99.95%) dihydrogen is obtained by:

• A. Electrolysis of acidified water using platinum electrodes
• B. Electrolyzing warm aq. $Ba(OH{)}_2$ using nickel anode and iron cathode
• C. Electrolysis of brine solution
• D. Reaction of steam on hydrocarbons or coke at high temperature in the presence of catalyst

Answer 1

The correct option is B Electrolyzing warm aq. $Ba(OH{)}_2$ using nickel anode and iron cathode

Very pure hydrogen is made by the electrolysis of water or solutions of a base
like $Ba(OH{)}_2$ using nickel anode and iron cathode. This is very expensive and
thus finds use only if pure $H_2$ is needed.

Pure water does not conduct electricity well and thus the need for the base.
The gases collected should be separated by a diaphragm so they don't
react explosively to yield water again.