Question

why ratio of hydrogen to oxygen is 2:1 by volume when formed at cathode and anode

Answer 1

Because Water's chemical representation is H₂O. That means, each water molecule has 2 hydrogen atoms & 1 oxygen atom. When electricity passes through water, the H₂O molecule breaks up into 2 Hydrogen & 1 oxygen atoms. So their ratio is 2 : 1. As we see... 

At Cathode:

H⁺ + 1e⁻ → [H]
H + H → 2H → H₂

At Anode:

4OH⁻ - 4e⁻ → 2H₂O + O₂

Therefore, the ratio of hydrogen to oxygen is 2:1 by volume when formed at cathode and anode.

I hope it helps you ^_^

Answer 2

Answer:

2:1

Explanation:

Water contains two atoms of hydrogen and one atom of oxygen. Hence the volume of hydrogen and oxygen in water becomes 2:1.