Question

Highly pure Hydrogen (~99.9% ) can be obtained from:

• A. Electrolysis of water
• B. Electrolysis of heavy water
• C. Reacting Zn with Dil H₂SO₄
• D. All of the above

Answer 1

The correct option is A

Electrolysis of water

Very highly pure Hydrogen can be obtained from Electrolysis of water:

Cathode reaction: 2 x$\left[2H_{2}O\right(l)+2e^{-}\to H_2(g)+2O{H}^{-}(aq\left)\right]$

Anode reaction: $4O{H}^{-}\left(aq\right)\to O_2\left(g\right)+2H_{2}O\left(l\right)+4e^{-}$

Overall reaction: $2H_{2}O\left(l\right)\to 2H_2\left(g\right)+O_2\left(g\right)$

For a given temperature and pressure, the volume of $H_2$ evolved is twice as much as $O_2$