JEE Main · 2022 · 25 Jul 2022 · Shift 2 · Hydrogen

High purity (>99.95%) dihydrogen is obtained by

(A)reaction of zinc with aqueous alkali.
(B)electrolysis of acidified water using platinum electrodes.
(C)electrolysis of warm aqueous barium hydroxide solution between nickel electrodes.✓ Correct
(D)reaction of zinc with dilute acid.

Answer: (C)

Solution

High purity dihydrogen (>99.95%) is obtained by the electrolysis of warm aqueous

Ba (OH)_{2}

solution using nickel electrodes. This method produces very pure hydrogen gas.

Other methods:

Reaction of Zn with alkali or dilute acid produces hydrogen but with impurities
Electrolysis of acidified water gives pure hydrogen but the barium hydroxide method is specifically known for ultra-high purity

The answer is option (C).

JEE Main · 2022 · 25 Jul 2022 · Shift 2 · Single correct option