High purity (>99.95%) dihydrogen is obtained by
Reaction of zinc with aqueous alkali
Electrolysis of acidified water using platinum electrodes
Electrolysis of warm aqueous barium hydroxide solution between nickel electrodes
Reaction of zinc with dilute acid
The Correct Option is C
Solution and Explanation
The question asks how high purity (>99.95%) dihydrogen is obtained, and gives us several options to choose from. The correct answer is the Electrolysis of warm aqueous barium hydroxide solution between nickel electrodes. Let's understand why this is the correct choice, and why other options are not suitable for obtaining such high purity dihydrogen.
Electrolysis of Acidified Water using Platinum Electrodes: This process is commonly used to produce hydrogen gas. However, the hydrogen obtained from this method may contain traces of oxygen, which makes it less than 99.95% pure. Thus, it does not provide the required purity.
Reaction of Zinc with Aqueous Alkali or Dilute Acid: Both these chemical reactions produce hydrogen gas:
- Zn + 2NaOH → Na2ZnO2 + H2
- Zn + 2HCl → ZnCl2 + H2
Electrolysis of Warm Aqueous Barium Hydroxide Solution Between Nickel Electrodes: This is a less common method but highly effective for producing high-purity dihydrogen. Nickel electrodes do not decompose easily in this setup, and the reaction is not contaminated by other substances, thus producing hydrogen of very high purity (>99.95%). This makes it the correct answer to the question.
Thus, the use of barium hydroxide solution and nickel electrodes in electrolysis provides a clean reaction environment, leading to high-quality hydrogen gas production.
